Dual Adaptor for Phosphotyrosine and 3-Phosphoinositides Pleckstrin homology (PH) domain; DAPP1 (also known as PHISH/3' phosphoinositide-interacting SH2 domain-containing protein or Bam32) plays a role in B-cell activation and has potential roles in T-cell and mast cell function. DAPP1 promotes B cell receptor (BCR) induced activation of Rho GTPases Rac1 and Cdc42, which feed into mitogen-activated protein kinases (MAPK) activation pathways and affect cytoskeletal rearrangement. DAPP1can also regulate BCR-induced activation of extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK). DAPP1 contains an N-terminal SH2 domain and a C-terminal pleckstrin homology (PH) domain with a single tyrosine phosphorylation site located centrally. DAPP1 binds strongly to both PtdIns(3,4,5)P3 and PtdIns(3,4)P2. The PH domain is essential for plasma membrane recruitment of PI3K upon cell activation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 163 SLGTKEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQFDYSQERVNCFCLVFPFRTFYLCAK 242
Cdd:cd10573    1 SLGSKEGYLTKLGGIVKNWKTRWFVLRRNELKYFKTRGDTKPIRVLDLRECSSVQRDYSQGKVNCFCLVFPERTFYMYAN 80

                         90
                 ....*....|....*.
gi 158631203 243 TGVEADEWIKILRWKL 258
Cdd:cd10573   81 TEEEADEWVKLLKWKL 96

Dual Adaptor for Phosphotyrosine and 3-Phosphoinositides Pleckstrin homology (PH) domain; DAPP1 (also known as PHISH/3' phosphoinositide-interacting SH2 domain-containing protein or Bam32) plays a role in B-cell activation and has potential roles in T-cell and mast cell function. DAPP1 promotes B cell receptor (BCR) induced activation of Rho GTPases Rac1 and Cdc42, which feed into mitogen-activated protein kinases (MAPK) activation pathways and affect cytoskeletal rearrangement. DAPP1can also regulate BCR-induced activation of extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK). DAPP1 contains an N-terminal SH2 domain and a C-terminal pleckstrin homology (PH) domain with a single tyrosine phosphorylation site located centrally. DAPP1 binds strongly to both PtdIns(3,4,5)P3 and PtdIns(3,4)P2. The PH domain is essential for plasma membrane recruitment of PI3K upon cell activation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 163 SLGTKEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQFDYSQERVNCFCLVFPFRTFYLCAK 242
Cdd:cd10573    1 SLGSKEGYLTKLGGIVKNWKTRWFVLRRNELKYFKTRGDTKPIRVLDLRECSSVQRDYSQGKVNCFCLVFPERTFYMYAN 80

                         90
                 ....*....|....*.
gi 158631203 243 TGVEADEWIKILRWKL 258
Cdd:cd10573   81 TEEEADEWVKLLKWKL 96

SH2 domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 158631203   35 WYHGNLTRHAAEALLLSNGCDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEYT--GYSFKFGFNEFSSLKDFVKHF 109
Cdd:pfam00017   1 WYHGKISRQEAERLLLNGKPDGTFLVRESESTPGGYTLSVRDDGKVKHYKIQSTdnGGYYISGGVKFSSLAELVEHY 77

Pleckstrin homology domain; Domain commonly found in eukaryotic signalling proteins. The domain family possesses multiple functions including the abilities to bind inositol phosphates, and various proteins. PH domains have been found to possess inserted domains (such as in PLC gamma, syntrophins) and to be inserted within other domains. Mutations in Brutons tyrosine kinase (Btk) within its PH domain cause X-linked agammaglobulinaemia (XLA) in patients. Point mutations cluster into the positively charged end of the molecule around the predicted binding site for phosphatidylinositol lipids.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203   166 TKEGYLTKQG-GLVKTWKTRWFTLHRNELKYFKD---QMSPEPIRILDLTECSAVQFD--YSQERVNCFCLVFPFR-TFY 238
Cdd:smart00233   2 IKEGWLYKKSgGGKKSWKKRYFVLFNSTLLYYKSkkdKKSYKPKGSIDLSGCTVREAPdpDSSKKPHCFEIKTSDRkTLL 81

                           90
                   ....*....|....*..
gi 158631203   239 LCAKTGVEADEWIKILR 255
Cdd:smart00233  82 LQAESEEEREKWVEALR 98

Dual Adaptor for Phosphotyrosine and 3-Phosphoinositides Pleckstrin homology (PH) domain; DAPP1 (also known as PHISH/3' phosphoinositide-interacting SH2 domain-containing protein or Bam32) plays a role in B-cell activation and has potential roles in T-cell and mast cell function. DAPP1 promotes B cell receptor (BCR) induced activation of Rho GTPases Rac1 and Cdc42, which feed into mitogen-activated protein kinases (MAPK) activation pathways and affect cytoskeletal rearrangement. DAPP1can also regulate BCR-induced activation of extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK). DAPP1 contains an N-terminal SH2 domain and a C-terminal pleckstrin homology (PH) domain with a single tyrosine phosphorylation site located centrally. DAPP1 binds strongly to both PtdIns(3,4,5)P3 and PtdIns(3,4)P2. The PH domain is essential for plasma membrane recruitment of PI3K upon cell activation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 163 SLGTKEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQFDYSQERVNCFCLVFPFRTFYLCAK 242
Cdd:cd10573    1 SLGSKEGYLTKLGGIVKNWKTRWFVLRRNELKYFKTRGDTKPIRVLDLRECSSVQRDYSQGKVNCFCLVFPERTFYMYAN 80

                         90
                 ....*....|....*.
gi 158631203 243 TGVEADEWIKILRWKL 258
Cdd:cd10573   81 TEEEADEWVKLLKWKL 96

Src homology 2 (SH2) domain found in the Nck family; Nck proteins are adaptors that modulate actin cytoskeleton dynamics by linking proline-rich effector molecules to tyrosine kinases or phosphorylated signaling intermediates. There are two members known in this family: Nck1 (Nckalpha) and Nck2 (Nckbeta and Growth factor receptor-bound protein 4 (Grb4)). They are characterized by having 3 SH3 domains and a C-terminal SH2 domain. Nck1 and Nck2 have overlapping functions as determined by gene knockouts. Both bind receptor tyrosine kinases and other tyrosine-phosphorylated proteins through their SH2 domains. In addition they also bind distinct targets. Neuronal signaling proteins: EphrinB1, EphrinB2, and Disabled-1 (Dab-1) all bind to Nck-2 exclusively. And in the case of PDGFR, Tyr(P)751 binds to Nck1 while Tyr(P)1009 binds to Nck2. Nck1 and Nck2 have a role in the infection process of enteropathogenic Escherichia coli (EPEC). Their SH3 domains are involved in recruiting and activating the N-WASP/Arp2/3 complex inducing actin polymerization resulting in the production of pedestals, dynamic bacteria-presenting protrusions of the plasma membrane. A similar thing occurs in the vaccinia virus where motile plasma membrane projections are formed beneath the virus. Recently it has been shown that the SH2 domains of both Nck1 and Nck2 bind the G-protein coupled receptor kinase-interacting protein 1 (GIT1) in a phosphorylation-dependent manner. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  35 WYHGNLTRHAAEALLLSNGCDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEYTGYSFKFGFNEFSSLKDFVKHFANQPL 114
Cdd:cd09943    3 WYYGRITRHQAETLLNEHGHEGDFLIRDSESNPGDYSVSLKAPGRNKHFKVQVVDNVYCIGQRKFHTMDELVEHYKKAPI 82

                         90
                 ....*....|.
gi 158631203 115 IGSETGTLMVL 125
Cdd:cd09943   83 FTSEQGEKLYL 93

C-terminal Src homology 2 (C-SH2) domain found in SH2 domain Phosphatases (SHP) proteins; The SH2 domain phosphatases (SHP-1, SHP-2/Syp, Drosophila corkscrew (csw), and Caenorhabditis elegans Protein Tyrosine Phosphatase (Ptp-2)) are cytoplasmic signaling enzymes. They are both targeted and regulated by interactions of their SH2 domains with phosphotyrosine docking sites. These proteins contain two SH2 domains (N-SH2, C-SH2) followed by a tyrosine phosphatase (PTP) domain, and a C-terminal extension. Shp1 and Shp2 have two tyrosyl phosphorylation sites in their C-tails, which are phosphorylated differentially by receptor and nonreceptor PTKs. Csw retains the proximal tyrosine and Ptp-2 lacks both sites. Shp-binding proteins include receptors, scaffolding adapters, and inhibitory receptors. Some of these bind both Shp1 and Shp2 while others bind only one. Most proteins that bind a Shp SH2 domain contain one or more immuno-receptor tyrosine-based inhibitory motifs (ITIMs): [SIVL]xpYxx[IVL]. Shp1 N-SH2 domain blocks the catalytic domain and keeps the enzyme in the inactive conformation, and is thus believed to regulate the phosphatase activity of SHP-1. Its C-SH2 domain is thought to be involved in searching for phosphotyrosine activators. The SHP2 N-SH2 domain is a conformational switch; it either binds and inhibits the phosphatase, or it binds phosphoproteins and activates the enzyme. The C-SH2 domain contributes binding energy and specificity, but it does not have a direct role in activation. Csw SH2 domain function is essential, but either SH2 domain can fulfill this requirement. The role of the csw SH2 domains during Sevenless receptor tyrosine kinase (SEV) signaling is to bind Daughter of Sevenless rather than activated SEV. Ptp-2 acts in oocytes downstream of sheath/oocyte gap junctions to promote major sperm protein (MSP)-induced MAP Kinase (MPK-1) phosphorylation. Ptp-2 functions in the oocyte cytoplasm, not at the cell surface to inhibit multiple RasGAPs, resulting in sustained Ras activation. It is thought that MSP triggers PTP-2/Ras activation and ROS production to stimulate MPK-1 activity essential for oocyte maturation and that secreted MSP domains and Cu/Zn superoxide dismutases function antagonistically to control ROS and MAPK signaling. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  35 WYHGNLTRHAAEALLLSNGCDGSYLLRDSNETTGLYSLSVRAKDS-VKHFHVEYTGYSFKF-GFNEFSSLKDFVKHFANQ 112
Cdd:cd09931    2 WFHGHLSGKEAEKLLLEKGKPGSFLVRESQSKPGDFVLSVRTDDDkVTHIMIRCQGGKYDVgGGEEFDSLTDLVEHYKKN 81

                         90
                 ....*....|....*....
gi 158631203 113 PLIGSeTGTLMVLKHPYPR 131
Cdd:cd09931   82 PMVET-SGTVVHLKQPLNA 99

Pleckstrin homology (PH) domain; PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGG-LVKTWKTRWFTLHRNELKYFKDQMSP--EPIRILDLTECSAVQFDYSQERVNCFCLVFPF-RTFYLCAK 242
Cdd:cd00821    1 KEGYLLKRGGgGLKSWKKRWFVLFEGVLLYYKSKKDSsyKPKGSIPLSGILEVEEVSPKERPHCFELVTPDgRTYYLQAD 80

                         90
                 ....*....|..
gi 158631203 243 TGVEADEWIKIL 254
Cdd:cd00821   81 SEEERQEWLKAL 92

Tandem PH-domain-containing protein 2 Pleckstrin homology (PH) domain; The binding of TAPP2 (also called PLEKHA2) adaptors to PtdIns(3,4)P(2), but not PI(3,4, 5)P3, function as negative regulators of insulin and PI3K signalling pathways (i.e. TAPP/utrophin/syntrophin complex). TAPP2 contains two sequential PH domains in which the C-terminal PH domain specifically binds PtdIns(3,4)P2 with high affinity. The N-terminal PH domain does not interact with any phosphoinositide tested. They also contain a C-terminal PDZ-binding motif that interacts with several PDZ-binding proteins, including PTPN13 (known previously as PTPL1 or FAP-1) as well as the scaffolding proteins MUPP1 (multiple PDZ-domain-containing protein 1), syntrophin and utrophin. The members here are most sequence similar to TAPP2 proteins, but may not be actual TAPP2 proteins. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTE---CSAVQFDYSQervNCFCLVFPFRTFYLCAKT 243
Cdd:cd13255    8 KAGYLEKKGERRKTWKKRWFVLRPTKLAYYKNDKEYRLLRLIDLTDihtCTEVQLKKHD---NTFGIVTPARTFYVQADS 84

                         90       100
                 ....*....|....*....|....
gi 158631203 244 GVEADEWIKilrwKLSQIRKQLNQ 267
Cdd:cd13255   85 KAEMESWIS----AINLARQALRA 104

Pleckstrin homology (PH) domain containing, family H (with MyTH4 domain) members 1 and 2 (PLEKHH1) PH domain, repeat 1; PLEKHH1 and PLEKHH2 (also called PLEKHH1L) are thought to function in phospholipid binding and signal transduction. There are 3 Human PLEKHH genes: PLEKHH1, PLEKHH2, and PLEKHH3. There are many isoforms, the longest of which contain a FERM domain, a MyTH4 domain, two PH domains, a peroximal domain, a vacuolar domain, and a coiled coil stretch. The FERM domain has a cloverleaf tripart structure (FERM_N, FERM_M, FERM_C/N, alpha-, and C-lobe/A-lobe, B-lobe, C-lobe/F1, F2, F3). The C-lobe/F3 within the FERM domain is part of the PH domain family. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQ--MSPEPIRILDLTECSAVQfdySQERVNCFCLVFPFRTFYLCAKTG 244
Cdd:cd13282    1 KAGYLTKLGGKVKTWKRRWFVLKNGELFYYKSPndVIRKPQGQIALDGSCEIA---RAEGAQTFEIVTEKRTYYLTADSE 77

                         90
                 ....*....|
gi 158631203 245 VEADEWIKIL 254
Cdd:cd13282   78 NDLDEWIRVI 87

Tandem PH-domain-containing proteins 1 and 2 Pleckstrin homology (PH) domain, C-terminal repeat; The binding of TAPP1 (also called PLEKHA1/pleckstrin homology domain containing, family A (phosphoinositide binding specific) member 1) and TAPP2 (also called PLEKHA2) adaptors to PtdIns(3,4)P(2), but not PI(3,4, 5)P3, function as negative regulators of insulin and PI3K signalling pathways (i.e. TAPP/utrophin/syntrophin complex). TAPP1 and TAPP2 contain two sequential PH domains in which the C-terminal PH domain specifically binds PtdIns(3,4)P2 with high affinity. The N-terminal PH domain does not interact with any phosphoinositide tested. They also contain a C-terminal PDZ-binding motif that interacts with several PDZ-binding proteins, including PTPN13 (known previously as PTPL1 or FAP-1) as well as the scaffolding proteins MUPP1 (multiple PDZ-domain-containing protein 1), syntrophin and utrophin. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQ---FDYSQERVNCFCLVFPFRTFYLCAKT 243
Cdd:cd13271   10 KSGYCVKQGAVRKNWKRRFFILDDNTISYYKSETDKEPLRTIPLREVLKVHeclVKSLLMRDNLFEIITTSRTFYIQADS 89

                 ....*....
gi 158631203 244 GVEADEWIK 252
Cdd:cd13271   90 PEEMHSWIK 98

Pleckstrin homology domain; Domain commonly found in eukaryotic signalling proteins. The domain family possesses multiple functions including the abilities to bind inositol phosphates, and various proteins. PH domains have been found to possess inserted domains (such as in PLC gamma, syntrophins) and to be inserted within other domains. Mutations in Brutons tyrosine kinase (Btk) within its PH domain cause X-linked agammaglobulinaemia (XLA) in patients. Point mutations cluster into the positively charged end of the molecule around the predicted binding site for phosphatidylinositol lipids.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203   166 TKEGYLTKQG-GLVKTWKTRWFTLHRNELKYFKD---QMSPEPIRILDLTECSAVQFD--YSQERVNCFCLVFPFR-TFY 238
Cdd:smart00233   2 IKEGWLYKKSgGGKKSWKKRYFVLFNSTLLYYKSkkdKKSYKPKGSIDLSGCTVREAPdpDSSKKPHCFEIKTSDRkTLL 81

                           90
                   ....*....|....*..
gi 158631203   239 LCAKTGVEADEWIKILR 255
Cdd:smart00233  82 LQAESEEEREKWVEALR 98

Src homology 2 (SH2) domain found in Abelson murine lymphosarcoma virus (ABL) proteins; ABL-family proteins are highly conserved tyrosine kinases. Each ABL protein contains an SH3-SH2-TK (Src homology 3-Src homology 2-tyrosine kinase) domain cassette, which confers autoregulated kinase activity and is common among nonreceptor tyrosine kinases. Several types of posttranslational modifications control ABL catalytic activity, subcellular localization, and stability, with consequences for both cytoplasmic and nuclear ABL functions. Binding partners provide additional regulation of ABL catalytic activity, substrate specificity, and downstream signaling. By combining this cassette with actin-binding and -bundling domain, ABL proteins are capable of connecting phosphoregulation with actin-filament reorganization. Vertebrate paralogs, ABL1 and ABL2, have evolved to perform specialized functions. ABL1 includes nuclear localization signals and a DNA binding domain which is used to mediate DNA damage-repair functions, while ABL2 has additional binding capacity for actin and for microtubules to enhance its cytoskeletal remodeling functions. SH2 is involved in several autoinhibitory mechanism that constrain the enzymatic activity of the ABL-family kinases. In one mechanism SH2 and SH3 cradle the kinase domain while a cap sequence stabilizes the inactive conformation resulting in a locked inactive state. Another involves phosphatidylinositol 4,5-bisphosphate (PIP2) which binds the SH2 domain through residues normally required for phosphotyrosine binding in the linker segment between the SH2 and kinase domains. The SH2 domain contributes to ABL catalytic activity and target site specificity. It is thought that the ABL catalytic site and SH2 pocket have coevolved to recognize the same sequences. Recent work now supports a hierarchical processivity model in which the substrate target site most compatible with ABL kinase domain preferences is phosphorylated with greatest efficiency. If this site is compatible with the ABL SH2 domain specificity, it will then reposition and dock in the SH2 pocket. This mechanism also explains how ABL kinases phosphorylates poor targets on the same substrate if they are properly positioned and how relatively poor substrate proteins might be recruited to ABL through a complex with strong substrates that can also dock with the SH2 pocket. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  35 WYHGNLTRHAAEaLLLSNGCDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEYTGYSFKFGFNE--FSSLKDFVKHFANQ 112
Cdd:cd09935    5 WYHGPISRNAAE-YLLSSGINGSFLVRESESSPGQYSISLRYDGRVYHYRISEDSDGKVYVTQEhrFNTLAELVHHHSKN 83

                         90
                 ....*....|....*.
gi 158631203 113 PligseTGTLMVLKHP 128
Cdd:cd09935   84 A-----DGLITTLRYP 94

Fungal proteins Pleckstrin homology (PH) domain, repeat 1; The functions of these fungal proteins are unknown, but they all contain 2 PH domains. This cd represents the first PH repeat. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQFDYSQERVNCFCLVFPFRTFYLCAKTGVE 246
Cdd:cd13298    8 KSGYLLKRSRKTKNWKKRWVVLRPCQLSYYKDEKEYKLRRVINLSELLAVAPLKDKKRKNVFGIYTPSKNLHFRATSEKD 87

                 ....*....
gi 158631203 247 ADEWIKILR 255
Cdd:cd13298   88 ANEWVEALR 96

PH domain; PH stands for pleckstrin homology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  166 TKEGYLTKQG-GLVKTWKTRWFTLHRNELKYFKDQMSP---EPIRILDLTECSAVQF--DYSQERVNCFCLVF----PFR 235
Cdd:pfam00169   2 VKEGWLLKKGgGKKKSWKKRYFVLFDGSLLYYKDDKSGkskEPKGSISLSGCEVVEVvaSDSPKRKFCFELRTgertGKR 81

                          90       100
                  ....*....|....*....|
gi 158631203  236 TFYLCAKTGVEADEWIKILR 255
Cdd:pfam00169  82 TYLLQAESEEERKDWIKAIQ 101

C-terminal Src homology 2 (C-SH2) domain in Phospholipase C gamma; Phospholipase C gamma is a signaling molecule that is recruited to the C-terminal tail of the receptor upon autophosphorylation of a highly conserved tyrosine. PLCgamma is composed of a Pleckstrin homology (PH) domain followed by an elongation factor (EF) domain, 2 catalytic regions of PLC domains that flank 2 tandem SH2 domains (N-SH2, C-SH2), and ending with a SH3 domain and C2 domain. N-SH2 SH2 domain-mediated interactions represent a crucial step in transmembrane signaling by receptor tyrosine kinases. SH2 domains recognize phosphotyrosine (pY) in the context of particular sequence motifs in receptor phosphorylation sites. Both N-SH2 and C-SH2 have a very similar binding affinity to pY. But in growth factor stimulated cells these domains bind to different target proteins. N-SH2 binds to pY containing sites in the C-terminal tails of tyrosine kinases and other receptors. Recently it has been shown that this interaction is mediated by phosphorylation-independent interactions between a secondary binding site found exclusively on the N-SH2 domain and a region of the FGFR1 tyrosine kinase domain. This secondary site on the SH2 cooperates with the canonical pY site to regulate selectivity in mediating a specific cellular process. C-SH2 binds to an intramolecular site on PLCgamma itself which allows it to hydrolyze phosphatidylinositol-4,5-bisphosphate into diacylglycerol and inositol triphosphate. These then activate protein kinase C and release calcium. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  35 WYHGNLTRHAAEALLLSNGCDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEYTGYSFKFGFNEFSSLKDFVKHFANQPL 114
Cdd:cd09932    6 WFHANLTREQAEEMLMRVPRDGAFLVRPSETDPNSFAISFRAEGKIKHCRIKQEGRLFVIGTSQFESLVELVSYYEKHPL 85

                         90
                 ....*....|....*....
gi 158631203 115 IGSetgtlMVLKHPYPRKV 133
Cdd:cd09932   86 YRK-----IKLRYPVNEEL 99

N-terminal Src homology 2 (SH2) domain found in SH2 domains, ANK, and kinase domain (shark) proteins; These non-receptor protein-tyrosine kinases contain two SH2 domains, five ankyrin (ANK)-like repeats, and a potential tyrosine phosphorylation site in the carboxyl-terminal tail which resembles the phosphorylation site in members of the src family. Like, mammalian non-receptor protein-tyrosine kinases, ZAP-70 and syk proteins, they do not have SH3 domains. However, the presence of ANK makes these unique among protein-tyrosine kinases. Both tyrosine kinases and ANK repeats have been shown to transduce developmental signals, and SH2 domains are known to participate intimately in tyrosine kinase signaling. These tyrosine kinases are believed to be involved in epithelial cell polarity. The members of this family include the shark (SH2 domains, ANK, and kinase domain) gene in Drosophila and yellow fever mosquitos, as well as the hydra protein HTK16. Drosophila Shark is proposed to transduce intracellularly the Crumbs, a protein necessary for proper organization of ectodermal epithelia, intercellular signal. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  33 LGWYHGNLTRHAAEALLL-SNGCDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEYTG---YSFKFGFNEFSSLKDFVKH 108
Cdd:cd10347    1 LRWYHGKISREVAEALLLrEGGRDGLFLVRESTSAPGDYVLSLLAQGEVLHYQIRRHGedaFFSDDGPLIFHGLDTLIEH 80

                 .
gi 158631203 109 F 109
Cdd:cd10347   81 Y 81

Sesquipedalian family Pleckstrin homology (PH) domain; The sesquipedalian family has 2 mammalian members: Ses1 and Ses2, which are also callled 7 kDa inositol polyphosphate phosphatase-interacting protein 1 and 2. They play a role in endocytic trafficking and are required for receptor recycling from endosomes, both to the trans-Golgi network and the plasma membrane. Members of this family form homodimers and heterodimers. Sesquipedalian interacts with inositol polyphosphate 5-phosphatase OCRL-1 (INPP5F) also known as Lowe oculocerebrorenal syndrome protein, a phosphatase enzyme that is involved in actin polymerization and is found in the trans-Golgi network and INPP5B. Sesquipedalian contains a single PH domain. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSaVQFDYSQERvNCFCLVFP---FRTFYLCAKT 243
Cdd:cd13288   10 KEGYLWKKGERNTSYQKRWFVLKGNLLFYFEKKGDREPLGVIVLEGCT-VELAEDAEP-YAFAIRFDgpgARSYVLAAEN 87

                         90
                 ....*....|..
gi 158631203 244 GVEADEWIKILR 255
Cdd:cd13288   88 QEDMESWMKALS 99

Myosin X Pleckstrin homology (PH) domain, repeat 2; MyoX, a MyTH-FERM myosin, is a molecular motor that has crucial functions in the transport and/or tethering of integrins in the actin-based extensions known as filopodia, microtubule binding, and in netrin-mediated axon guidance. It functions as a dimer. MyoX walks on bundles of actin, rather than single filaments, unlike the other unconventional myosins. MyoX is present in organisms ranging from humans to choanoflagellates, but not in Drosophila and Caenorhabditis elegans.MyoX consists of a N-terminal motor/head region, a neck made of 3 IQ motifs, and a tail consisting of a coiled-coil domain, a PEST region, 3 PH domains, a myosin tail homology 4 (MyTH4), and a FERM domain at its very C-terminus. The first PH domain in the MyoX tail is a split-PH domain, interupted by the second PH domain such that PH 1a and PH 1b flanks PH 2. The third PH domain (PH 3) follows the PH 1b domain. This cd contains the second PH repeat. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLV-----KTWKTRWFTLHRNELKYFK-DQMSPEPIRILDLTECSAVqFDYSQERvNCFCLVFPFRTFYLC 240
Cdd:cd13296    1 KSGWLTKKGGGSstlsrRNWKSRWFVLRDTVLKYYEnDQEGEKLLGTIDIRSAKEI-VDNDPKE-NRLSITTEERTYHLV 78

                         90
                 ....*....|....
gi 158631203 241 AKTGVEADEWIKIL 254
Cdd:cd13296   79 AESPEDASQWVNVL 92

Src homology 2 (SH2) domain in the Breast Cancer Anti-estrogen Resistance protein 3; BCAR3 is part of a growing family of guanine nucleotide exchange factors is responsible for activation of Ras-family GTPases, including Sos1 and 2, GRF1 and 2, CalDAG-GEF/GRP1-4, C3G, cAMP-GEF/Epac 1 and 2, PDZ-GEFs, MR-GEF, RalGDS family members, RalGPS, RasGEF, Smg GDS, and phospholipase C(epsilon). 12102558 21262352 BCAR3 binds to the carboxy-terminus of BCAR1/p130Cas, a focal adhesion adapter protein. Over expression of BCAR1 (p130Cas) and BCAR3 induces estrogen independent growth in normally estrogen-dependent cell lines. They have been linked to resistance to anti-estrogens in breast cancer, Rac activation, and cell motility, though the BCAR3/p130Cas complex is not required for this activity in BCAR3. Many BCAR3-mediated signaling events in epithelial and mesenchymal cells are independent of p130Cas association. Structurally these proteins contain a single SH2 domain upstream of their RasGEF domain, which is responsible for the ability of BCAR3 to enhance p130Cas over-expression-induced migration. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  28 ELLQDLGWYHGNLTRHAAEALLLSngcDGSYLLRDSNETTGLYSLSVRAKDSVKHFHV---------EYTGYSFKFGFNE 98
Cdd:cd10337    1 EDLRSHAWYHGRIPRQVAESLVQR---EGDFLVRDSLSSPGDYVLTCRWKGQPLHFKInrvvlrpseAYTRVQYQFEDEQ 77

                         90
                 ....*....|.
gi 158631203  99 FSSLKDFVKHF 109
Cdd:cd10337   78 FDSIPALVHFY 88

Set binding factor 1 (also called Human MTMR5) Pleckstrin Homology (PH) domain; Sbf1 is a myotubularin-related pseudo-phosphatase. Both Sbf1 and myotubularin interact with the SET domains of Hrx and other epigenetic regulatory proteins, but Sbf1 lacks phosphatase activity due to several amino acid changes in its structurally preserved catalytic pocket. It contains pleckstrin (PH), GEF, and myotubularin homology domains that are thought to be responsible for signaling and growth control. Sbf1 functions as an inhibitor of cellular growth. The N-terminal GEF homology domain serves to inhibit the transforming effects of Sbf1. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 166 TKEGYLTKQGGLVKTWKTRWFTLH--RNELKYFKDQMSPEPIRILDLTECSAVQF--------DYSQERVNcFCLVFPFR 235
Cdd:cd01235    4 THEGYLYKRGALLKGWKQRWFVLDstKHQLRYYESREDTKCKGFIDLAEVESVTPatpiigapKRADEGAF-FDLKTNKR 82

                         90
                 ....*....|....*.
gi 158631203 236 TFYLCAKTGVEADEWI 251
Cdd:cd01235   83 VYNFCAFDAESAQQWI 98

Src homology 2 (SH2) domain found in the Src oncogene at 42A (Src42); Src42 is a member of the Src non-receptor type tyrosine kinase family of proteins. The integration of receptor tyrosine kinase-induced RAS and Src42 signals by Connector eNhancer of KSR (CNK) as a two-component input is essential for RAF activation in Drosophila. Src42 is present in a wide variety of organisms including: California sea hare, pea aphid, yellow fever mosquito, honey bee, Panamanian leafcutter ant, and sea urchin. Src42 has a unique N-terminal domain, an SH3 domain, an SH2 domain, a kinase domain and a regulatory tail, as do the other members of the family. Like the other members of the Src family the SH2 domain in addition to binding the target, also plays an autoinhibitory role by binding to its C-terminal tail. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  35 WYHGNLTRHAAEALLLSNGCD-GSYLLRDSNETTGLYSLSVRAKDSVKHFHV---EYTGYsFKFGFNEFSSLKDFVKHFA 110
Cdd:cd10370    5 WYFGKIKRIEAEKKLLLPENEhGAFLIRDSESRHNDYSLSVRDGDTVKHYRIrqlDEGGF-FIARRTTFRTLQELVEHYS 83

                 ...
gi 158631203 111 NQP 113
Cdd:cd10370   84 KDS 86

Rho GTPase activating protein 24 Pleckstrin homology (PH) domain; RhoGap24 (also called ARHGAP24, p73RhoGAp, and Filamin-A-associated RhoGAP) like other RhoGAPs are involved in cell polarity, cell morphology and cytoskeletal organization. They act as GTPase activators for the Rac-type GTPases by converting them to an inactive GDP-bound state and control actin remodeling by inactivating Rac downstream of Rho leading to suppress leading edge protrusion and promotes cell retraction to achieve cellular polarity and are able to suppress RAC1 and CDC42 activity in vitro. Overexpression of these proteins induces cell rounding with partial or complete disruption of actin stress fibers and formation of membrane ruffles, lamellipodia, and filopodia. Members here contain an N-terminal PH domain followed by a RhoGAP domain and either a BAR or TATA Binding Protein (TBP) Associated Factor 4 (TAF4) domain. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQFDYSQERVNCFCL-VFP----------FR 235
Cdd:cd13379    5 KCGWLRKQGGFVKTWHTRWFVLKGDQLYYFKDEDETKPLGTIFLPGNRVTEHPCNEEEPGKFLFeVVPggdrermtanHE 84

                         90       100
                 ....*....|....*....|
gi 158631203 236 TFYLCAKTGVEADEWIKILR 255
Cdd:cd13379   85 TYLLMASTQNDMEDWVKSIR 104

Src homology 2 (SH2) domain found in Fyn isoform a like proteins; Fyn is a member of the Src non-receptor type tyrosine kinase family of proteins. This cd contains the SH2 domain found in Fyn isoform a type proteins. Fyn is involved in the control of cell growth and is required in the following pathways: T and B cell receptor signaling, integrin-mediated signaling, growth factor and cytokine receptor signaling, platelet activation, ion channel function, cell adhesion, axon guidance, fertilization, entry into mitosis, and differentiation of natural killer cells, oligodendrocytes and keratinocytes. The protein associates with the p85 subunit of phosphatidylinositol 3-kinase and interacts with the Fyn-binding protein. Alternatively spliced transcript variants encoding distinct isoforms exist. Fyn is primarily localized to the cytoplasmic leaflet of the plasma membrane. Tyrosine phosphorylation of target proteins by Fyn serves to either regulate target protein activity, and/or to generate a binding site on the target protein that recruits other signaling molecules. FYN has been shown to interact with a number of proteins including: BCAR1, Cbl, Janus kinase, nephrin, Sky, tyrosine kinase, Wiskott-Aldrich syndrome protein, and Zap-70. Fyn has a unique N-terminal domain, an SH3 domain, an SH2 domain, a kinase domain and a regulatory tail, as do the other members of the family. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203  35 WYHGNLTRHAAEALLLSNG-CDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEY-------TGYSFKFGFNEFSSLKDFV 106
Cdd:cd10418    5 WYFGKLGRKDAERQLLSFGnPRGTFLIRESETTKGAYSLSIRDWDDMKGDHVKHykirkldNGGYYITTRAQFETLQQLV 84

                 ....*.
gi 158631203 107 KHFANQ 112
Cdd:cd10418   85 QHYSER 90

N-terminal Src homology 2 (SH2) domain found in Ras GTPase-activating protein 1 (GAP); RasGAP is part of the GAP1 family of GTPase-activating proteins. The protein is located in the cytoplasm and stimulates the GTPase activity of normal RAS p21, but not its oncogenic counterpart. Acting as a suppressor of RAS function, the protein enhances the weak intrinsic GTPase activity of RAS proteins resulting in RAS inactivation, thereby allowing control of cellular proliferation and differentiation. Mutations leading to changes in the binding sites of either protein are associated with basal cell carcinomas. Alternative splicing results in two isoforms. The shorter isoform which lacks the N-terminal hydrophobic region, has the same activity, and is expressed in placental tissues. In general the longer isoform contains 2 SH2 domains, a SH3 domain, a pleckstrin homology (PH) domain, and a calcium-dependent phospholipid-binding C2 domain. The C-terminus contains the catalytic domain of RasGap which catalyzes the activation of Ras by hydrolyzing GTP-bound active Ras into an inactive GDP-bound form of Ras. This model contains the N-terminal SH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 158631203  35 WYHGNLTRHAAEALLLSNGCDGSYLLRDSNETTGLYSLSVRAKDSVKHFHVEYTGYSFKFGFNEFSSLKDFVKHFA 110
Cdd:cd10353   21 WYHGRLDRTIAEERLRQAGKLGSYLIRESDRRPGSFVLSFLSRTGVNHFRIIAMCGDYYIGGRRFSSLSDLIGYYS 96

Src homology 2 (SH2) domain found in SH2-containing inositol-5'-phosphatase (SHIP) and SLAM-associated protein (SAP); The SH2-containing inositol-5'-phosphatase, SHIP (also called SHIP1/SHIP1a), is a hematopoietic-restricted phosphatidylinositide phosphatase that translocates to the plasma membrane after extracellular stimulation and hydrolyzes the phosphatidylinositol-3-kinase (PI3K)-generated second messenger PI-3,4,5-P3 (PIP3) to PI-3,4-P2. As a result, SHIP dampens down PIP3 mediated signaling and represses the proliferation, differentiation, survival, activation, and migration of hematopoietic cells. PIP3 recruits lipid-binding pleckstrin homology(PH) domain-containing proteins to the inner wall of the plasma membrane and activates them. PH domain-containing downstream effectors include the survival/proliferation enhancing serine/threonine kinase, Akt (protein kinase B), the tyrosine kinase, Btk, the regulator of protein translation, S6K, and the Rac and cdc42 guanine nucleotide exchange factor, Vav. SHIP is believed to act as a tumor suppressor during leukemogenesis and lymphomagenesis, and may play a role in activating the immune system to combat cancer. SHIP contains an N-terminal SH2 domain, a centrally located phosphatase domain that specifically hydrolyzes the 5'-phosphate from PIP3, PI-4,5-P2 and inositol-1,3,4,5- tetrakisphosphate (IP4), a C2 domain, that is an allosteric activating site when bound by SHIP's enzymatic product, PI-3,4-P2; 2 NPXY motifs that bind proteins with a phosphotyrosine binding (Shc, Dok 1, Dok 2) or an SH2 (p85a, SHIP2) domain; and a proline-rich domain consisting of four PxxP motifs that bind a subset of SH3-containing proteins including Grb2, Src, Lyn, Hck, Abl, PLCg1, and PIAS1. The SH2 domain of SHIP binds to the tyrosine phosphorylated forms of Shc, SHP-2, Doks, Gabs, CD150, platelet-endothelial cell adhesion molecule, Cas, c-Cbl, immunoreceptor tyrosine-based inhibitory motifs (ITIMs), and immunoreceptor tyrosine-based activation motifs (ITAMs). The X-linked lymphoproliferative syndrome (XLP) gene encodes SAP (also called SH2D1A/DSHP) a protein that consists of a 5 residue N-terminus, a single SH2 domain, and a short 25 residue C-terminal tail. XLP is characterized by an extreme sensitivity to Epstein-Barr virus. Both T and natural killer (NK) cell dysfunctions have been seen in XLP patients. SAP binds the cytoplasmic tail of Signaling lymphocytic activation molecule (SLAM), 2B4, Ly-9, and CD84. SAP is believed to function as a signaling inhibitor, by blocking or regulating binding of other signaling proteins. SAP and the SAP-like protein EAT-2 recognize the sequence motif TIpYXX(V/I), which is found in the cytoplasmic domains of a restricted number of T, B, and NK cell surface receptors and are proposed to be natural inhibitors or regulators of the physiological role of a small family of receptors on the surface of these cells. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 158631203  31 QDLGWYHGNLTRHAAEALLLSNGCDGSYLLRDSNETTGLYSLSV 74
Cdd:cd10343    1 MAPPWYHGNITRSKAEELLSKAGKDGSFLVRDSESVSGAYALCV 44

SH3 domain-binding protein 2 Pleckstrin homology (PH) domain; SH3BP2 (the gene that encodes the adaptor protein 3BP2), HD, ITU, IT10C3, and ADD1 are located near the Huntington's Disease Gene on Human Chromosome 4pl6.3. SH3BP2 lies in a region that is often missing in individuals with Wolf-Hirschhorn syndrome (WHS). Gain of function mutations in SH3BP2 causes enhanced B-cell antigen receptor (BCR)-mediated activation of nuclear factor of activated T cells (NFAT), resulting in a rare, genetic disorder called cherubism. This results in an increase in the signaling complex formation with Syk, phospholipase C-gamma2 (PLC-gamma2), and Vav1. It was recently discovered that Tankyrase regulates 3BP2 stability through ADP-ribosylation and ubiquitylation by the E3-ubiquitin ligase. Cherubism mutations uncouple 3BP2 from Tankyrase-mediated protein destruction, which results in its stabilization and subsequent hyperactivation of the Src, Syk, and Vav signaling pathways. SH3BP2 is also a potential negative regulator of the abl oncogene. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 166 TKEGYLTKQGGLVKT---WKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSAVQfdySQERvnCFCLVFPF-------- 234
Cdd:cd13308   10 IHSGTLTKKGGSQKTlqnWQLRYVIIHQGCVYYYKNDQSAKPKGVFSLNGYNRRA---AEER--TSKLKFVFkiihlspd 84

                         90       100
                 ....*....|....*....|..
gi 158631203 235 -RTFYLCAKTGVEADEWIKILR 255
Cdd:cd13308   85 hRTWYFAAKSEDEMSEWMEYIR 106

Grb2-associated binding protein 3 pleckstrin homology (PH) domain; The Gab subfamily includes several Gab proteins, Drosophila DOS and C. elegans SOC-1. They are scaffolding adaptor proteins, which possess N-terminal PH domains and a C-terminus with proline-rich regions and multiple phosphorylation sites. Following activation of growth factor receptors, Gab proteins are tyrosine phosphorylated and activate PI3K, which generates 3-phosphoinositide lipids. By binding to these lipids via the PH domain, Gab proteins remain in proximity to the receptor, leading to further signaling. While not all Gab proteins depend on the PH domain for recruitment, it is required for Gab activity. The members in this cd include the Gab1, Gab2, and Gab3 proteins. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 181 WKTRWFTLHRNE-------LKYFKDQMSPEPIRILDLTECSAVQFD----YSQERVNCFCLVFP--FRTFYLCAKTGVEA 247
Cdd:cd13385   26 WRKRWFVLRRGRmsgnpdvLEYYRNNHSKKPIRVIDLSECEVLKHSgpnfIRKEFQNNFVFIVKttYRTFYLVAKTEEEM 105

                         90       100
                 ....*....|....*....|....
gi 158631203 248 DEWIKilrwKLSQIrkqLNQGEGT 271
Cdd:cd13385  106 QVWVH----NISQI---CNFGHLE 122

RAS p21 protein activator (GTPase activating protein) family pleckstrin homology (PH) domain; RASAL1, GAP1(m), GAP1(IP4BP), and CAPRI are all members of the GAP1 family of GTPase-activating proteins. They contain N-terminal SH2-SH3-SH2 domains, followed by two C2 domains, a PH domain, a RasGAP domain, and a BTK domain. With the notable exception of GAP1(m), they all possess an arginine finger-dependent GAP activity on the Ras-related protein Rap1. They act as a suppressor of RAS enhancing the weak intrinsic GTPase activity of RAS proteins resulting in the inactive GDP-bound form of RAS, allowing control of cellular proliferation and differentiation. PH domains share little sequence conservation, but all have a common fold, which is electrostatically polarized. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

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gi 158631203 167 KEGYLTK--QGGL----VKTWKTRWFTLHRNELKYFKDQMSpEPIRILDLTECSAVqfdysqERV--------NCFCLVF 232
Cdd:cd01244    1 KEGYLIKraQGRKkkfgRKNFKKRYFRLTNEALSYSKSKGK-QPLCSIPLEDILAV------ERVeeesfkmkNMFQIVQ 73

                         90       100
                 ....*....|....*....|....*...
gi 158631203 233 PFRTFYLCAKTGVEADEWIKILRwKLSQ 260
Cdd:cd01244   74 PDRTLYLQAKNVVELNEWLSALR-KVCL 100

Pleckstrin 2 Pleckstrin homology (PH) domain, repeat 1; Pleckstrin is a protein found in platelets. This name is derived from platelet and leukocyte C kinase substrate and the KSTR string of amino acids. Pleckstrin 2 contains two PH domains and a DEP (dishvelled, egl-10, and pleckstrin) domain. Unlike pleckstrin 1, pleckstrin 2 does not contain obvious sites of PKC phosphorylation. Pleckstrin 2 plays a role in actin rearrangement, large lamellipodia and peripheral ruffle formation, and may help orchestrate cytoskeletal arrangement. The PH domains of pleckstrin 2 are thought to contribute to lamellipodia formation. This cd contains the first PH domain repeat. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 167 KEGYLTKQGGLVKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSavqfdysqerVNCFCLVFPFRTF--------- 237
Cdd:cd13301    5 KEGYLVKKGHVVNNWKARWFVLKEDGLEYYKKKTDSSPKGMIPLKGCT----------ITSPCLEYGKRPLvfklttakg 74

                         90
                 ....*....|....*...
gi 158631203 238 ---YLCAKTGVEADEWIK 252
Cdd:cd13301   75 qehFFQACSREERDAWAK 92

ArfGAP with RhoGAP domain, ankyrin repeat and PH domain Pleckstrin homology (PH) domain, repeat 1; ARAP proteins (also called centaurin delta) are phosphatidylinositol 3,4,5-trisphosphate-dependent GTPase-activating proteins that modulate actin cytoskeleton remodeling by regulating ARF and RHO family members. They bind phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) and phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4,5)P2) binding. There are 3 mammalian ARAP proteins: ARAP1, ARAP2, and ARAP3. All ARAP proteins contain a N-terminal SAM (sterile alpha motif) domain, 5 PH domains, an ArfGAP domain, 2 ankyrin domain, A RhoGap domain, and a Ras-associating domain. This hierarchy contains the first PH domain in ARAP. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 158631203 166 TKEGYLTKQGGL--VKTWKTRWFTLHRNELKYFKDQMSPEPIRILDLTECSavqfDYSQERVNCFCLVFPFRTFYLCAKT 243
Cdd:cd13253    1 IKSGYLDKQGGQgnNKGFQKRWVVFDGLSLRYFDSEKDAYSKRIIPLSAIS----TVRAVGDNKFELVTTNRTFVFRAES 76