Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142   226 PPVIVVPPKNSTVNASQDVSLACHAEAYPANlTYSWFQDNINVFHiSRLQPRVRILVDGSLRLLATQPDDAGCYTCVPSN 305
Cdd:pfam13927    1 KPVITVSPSSVTVREGETVTLTCEATGSPPP-TITWYKNGEPISS-GSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  609 SPPRGL-VAVRTPRGVLLHWDPPELVPKRLDGYVLE-GRQGSQGWEVLDPaVAGTETELLVPGLIKDVLYEFRLVAFAGS 686
Cdd:cd00063     2 SPPTNLrVTDVTSTSVTLSWTPPEDDGGPITGYVVEyREKGSGDWKEVEV-TPGSETSYTLTGLKPGTEYEFRVRAVNGG 80

                          90
                  ....*....|...
gi 119573142  687 FVSDPSNTANVST 699
Cdd:cd00063    81 GESPPSESVTVTT 93

Fibronectin type 3 domain [General function prediction only];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  466 GHWECSASNAVARVATSTNVYVLGTSPHVVTNVSVVALPkGANVSWEPGFDGGYLQRFSVWYTPLAKRPDRMHHDWV--- 542
Cdd:COG3401   105 GATNTGLTSSDEVPSPAVGTATTATAVAGGAATAGTYAL-GAGLYGVDGANASGTTASSVAGAGVVVSPDTSATAAVatt 183

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  543 SLAVPVGAAHLLVPGLQPHTQYQFSVLAQNKLGSGPFSEIVLsapeglpttpaapGLPPTEIPpplSPPRGLVA-VRTPR 621
Cdd:COG3401   184 SLTVTSTTLVDGGGDIEPGTTYYYRVAATDTGGESAPSNEVS-------------VTTPTTPP---SAPTGLTAtADTPG 247

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  622 GVLLHWDPPELvpKRLDGYVLEGRQGSQG-WEVLDpavAGTETELLVPGLIKDVLYEFRLVAFAGSFV-SDPSNTANVST 699
Cdd:COG3401   248 SVTLSWDPVTE--SDATGYRVYRSNSGDGpFTKVA---TVTTTSYTDTGLTNGTTYYYRVTAVDAAGNeSAPSNVVSVTT 322

                  ..
gi 119573142  700 SG 701
Cdd:COG3401   323 DL 324

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142     28 SVVGRAGESVVLGCdllPPAGRPPLHvIEWLRFGFLLPIfiqfglYSPRIDPDYVGRvrlqkGASLQIEGLRVEDQGWYE 107
Cdd:smart00410    3 SVTVKEGESVTLSC---EASGSPPPE-VTWYKQGGKLLA------ESGRFSVSRSGS-----TSTLTISNVTPEDSGTYT 67

                    ...
gi 119573142    108 CRV 110
Cdd:smart00410   68 CAA 70

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142   226 PPVIVVPPKNSTVNASQDVSLACHAEAYPANlTYSWFQDNINVFHiSRLQPRVRILVDGSLRLLATQPDDAGCYTCVPSN 305
Cdd:pfam13927    1 KPVITVSPSSVTVREGETVTLTCEATGSPPP-TITWYKNGEPISS-GSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142    143 PAVLEVQELEPVTLRCVARGSPLPHVTWKLRGKDLGQGQG----QVQVQNGTLRIRRVERGSSGVYTCQASSTEGSATHA 218
Cdd:smart00410    1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGrfsvSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

                    ....*
gi 119573142    219 TQLLV 223
Cdd:smart00410   81 TTLTV 85

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  609 SPPRGL-VAVRTPRGVLLHWDPPELVPKRLDGYVLE-GRQGSQGWEVLDPaVAGTETELLVPGLIKDVLYEFRLVAFAGS 686
Cdd:cd00063     2 SPPTNLrVTDVTSTSVTLSWTPPEDDGGPITGYVVEyREKGSGDWKEVEV-TPGSETSYTLTGLKPGTEYEFRVRAVNGG 80

                          90
                  ....*....|...
gi 119573142  687 FVSDPSNTANVST 699
Cdd:cd00063    81 GESPPSESVTVTT 93

Fifth Ig-like domain of Roundabout (Robo) homolog 1/2, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth Ig-like domain of Roundabout (Robo) homolog 1/2 and similar domains. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, -2, and -3), and three mammalian Slit homologs (Slit-1,-2, -3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, -2, and -3 are expressed by commissural neurons in the vertebrate spinal cord and Slits 1, -2, -3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of slit responsiveness, antagonizes slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. The fifth Ig-like domain of Robo 1 and 2 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  228 VIVVPPKNSTVNASQDVSLACHAEAYPANlTYSWFQDNinvFHISRLQPRVRILVDGSLRLLATQPDDAGCYTCVPSNgL 307
Cdd:cd20952     1 IILQGPQNQTVAVGGTVVLNCQATGEPVP-TISWLKDG---VPLLGKDERITTLENGSLQIKGAEKSDTGEYTCVALN-L 75

                          90
                  ....*....|..
gi 119573142  308 LHPPSASAYLTV 319
Cdd:cd20952    76 SGEATWSAVLDV 87

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 119573142   405 IERPKEEYFQEVGRELLIPCSAQGDPPPVVSWTKVGRGLQGQAQ-----VDSNSSLILRPLTKEAHGHWECSASN 474
Cdd:pfam13927    4 ITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTrsrslSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM) and similar proteins; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the first immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, or spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains NrCAM [Ng(neuronglia)CAM-related cell adhesion molecule], which is primarily expressed in the nervous system, and human neurofascin. This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lacks a C" strand.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 119573142  325 VIRCPVRANPPLLFvSWTKDGKALQLDKFPGWS-QGTEGSLIIALGN---EDALGEYSCTPYNSLGTA 388
Cdd:cd05733    20 TIKCEAKGNPQPTF-RWTKDGKFFDPAKDPRVSmRRRSGTLVIDNHNggpEDYQGEYQCYASNELGTA 86

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142    233 PKNSTVNASQDVSLACHAEAYPaNLTYSWFQDNINVFHISrlqPRVRILVDG---SLRLLATQPDDAGCYTCVPSNGlLH 309
Cdd:smart00410    1 PPSVTVKEGESVTLSCEASGSP-PPEVTWYKQGGKLLAES---GRFSVSRSGstsTLTISNVTPEDSGTYTCAATNS-SG 75

                            90
                    ....*....|
gi 119573142    310 PPSASAYLTV 319
Cdd:smart00410   76 SASSGTTLTV 85

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142    492 PHVVTNVSVVALPKG-ANVSWEPGFD---GGYLQRFSVWYTPLakrpdrmHHDWVSLAVPVGAAHLLVPGLQPHTQYQFS 567
Cdd:smart00060    1 PSPPSNLRVTDVTSTsVTLSWEPPPDdgiTGYIVGYRVEYREE-------GSEWKEVNVTPSSTSYTLTGLKPGTEYEFR 73

                            90
                    ....*....|
gi 119573142    568 VLAQNKLGSG 577
Cdd:smart00060   74 VRAVNGAGEG 83

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                            10        20        30        40        50        60        70
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 119573142    609 SPPRGLVAV-RTPRGVLLHWDPPEL--VPKRLDGYVLEGRQGSQGWEVLDpaVAGTETELLVPGLIKDVLYEFRLVAF 683
Cdd:smart00060    2 SPPSNLRVTdVTSTSVTLSWEPPPDdgITGYIVGYRVEYREEGSEWKEVN--VTPSSTSYTLTGLKPGTEYEFRVRAV 77

Fifth Ig-like domain of Roundabout (Robo) homolog 1/2, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth Ig-like domain of Roundabout (Robo) homolog 1/2 and similar domains. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, -2, and -3), and three mammalian Slit homologs (Slit-1,-2, -3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, -2, and -3 are expressed by commissural neurons in the vertebrate spinal cord and Slits 1, -2, -3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of slit responsiveness, antagonizes slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. The fifth Ig-like domain of Robo 1 and 2 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142   27 VSVVGRAGESVVLGCDllppAGRPPLHVIEWLRFGFLLPIfiqfglysprIDPdyvgRVRLQKGASLQIEGLRVEDQGWY 106
Cdd:cd20952     7 QNQTVAVGGTVVLNCQ----ATGEPVPTISWLKDGVPLLG----------KDE----RITTLENGSLQIKGAEKSDTGEY 68

                  ..
gi 119573142  107 EC 108
Cdd:cd20952    69 TC 70

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142   226 PPVIVVPPKNSTVNASQDVSLACHAEAYPANlTYSWFQDNINVFHiSRLQPRVRILVDGSLRLLATQPDDAGCYTCVPSN 305
Cdd:pfam13927    1 KPVITVSPSSVTVREGETVTLTCEATGSPPP-TITWYKNGEPISS-GSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142    143 PAVLEVQELEPVTLRCVARGSPLPHVTWKLRGKDLGQGQG----QVQVQNGTLRIRRVERGSSGVYTCQASSTEGSATHA 218
Cdd:smart00410    1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGrfsvSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

                    ....*
gi 119573142    219 TQLLV 223
Cdd:smart00410   81 TTLTV 85

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  609 SPPRGL-VAVRTPRGVLLHWDPPELVPKRLDGYVLE-GRQGSQGWEVLDPaVAGTETELLVPGLIKDVLYEFRLVAFAGS 686
Cdd:cd00063     2 SPPTNLrVTDVTSTSVTLSWTPPEDDGGPITGYVVEyREKGSGDWKEVEV-TPGSETSYTLTGLKPGTEYEFRVRAVNGG 80

                          90
                  ....*....|...
gi 119573142  687 FVSDPSNTANVST 699
Cdd:cd00063    81 GESPPSESVTVTT 93

Fourth immunoglobulin (Ig)-like domain of hemolin, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain of hemolin and similar proteins. Hemolin, an insect immunoglobulin superfamily (IgSF) member containing four Ig-like domains, is a lipopolysaccharide-binding immune protein induced during bacterial infection. Hemolin shares significant sequence similarity with the first four Ig-like domains of the transmembrane cell adhesion molecules (CAMs) of the L1 family. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The fourth Ig-like domain of hemolin is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 119573142  136 PQFQETPPAVLEVQELEPVTLRCVARGSPLPHVTWKLRGKDLGQGQGQVQVQNGTLRIRRVERGSSGVYTCQASSTEG 213
Cdd:cd20978     1 PKFIQKPEKNVVVKGGQDVTLPCQVTGVPQPKITWLHNGKPLQGPMERATVEDGTLTIINVQPEDTGYYGCVATNEIG 78

Fourth immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  135 PPQFQETppavLEVQELEP---VTLRCVARGSPLPHVTWKLRGKDLGQgqgqvqvqngTLRIR----------------- 194
Cdd:cd20956     1 APVLLET----FSEQTLQPgpsVSLKCVASGNPLPQITWTLDGFPIPE----------SPRFRvgdyvtsdgdvvsyvni 66

                          90       100       110
                  ....*....|....*....|....*....|..
gi 119573142  195 ---RVERGssGVYTCQASSTEGSATHATQLLV 223
Cdd:cd20956    67 ssvRVEDG--GEYTCTATNDVGSVSHSARINV 96

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 119573142  420 LLIPCSAQGDPPPVVSWTKVGRGLQGQAQ-----VDSNSSLILRPLTKEAHGHWECSASNAVARVATST 483
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLPPSSRdsrrsELGNGTLTISNVTLEDSGTYTCVASNSAGGSASAS 69

Fourth Ig-like domain from smooth muscle myosin light chain kinase and similar domains ; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain from smooth muscle myosin light chain kinase (MYLK) and similar domains. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of this group shows that the fourth Ig-like domain from myosin light chain kinase lacks this strand and thus belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  135 PPQFQETPPAvLEVQELEPVTLRCVARGSPLPHVTWKLRGKDLGQGQGQVQVQNGT--LRIRRVERGSSGVYTCQASSTE 212
Cdd:cd20976     1 APSFSSVPKD-LEAVEGQDFVAQCSARGKPVPRITWIRNAQPLQYAADRSTCEAGVgeLHIQDVLPEDHGTYTCLAKNAA 79

                          90
                  ....*....|.
gi 119573142  213 GSATHATQLLV 223
Cdd:cd20976    80 GQVSCSAWVTV 90

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 119573142   405 IERPKEEYFQEVGRELLIPCSAQGDPPPVVSWTKVGRGLQGQAQ-----VDSNSSLILRPLTKEAHGHWECSASN 474
Cdd:pfam13927    4 ITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTrsrslSGSNSTLTISNVTRSDAGTYTCVASN 78

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  492 PHVVTNVSVVALPKG-ANVSWE-PGFDGGYLQRFSVWYTPLAkrpdrmHHDWVSLAVPVGAA-HLLVPGLQPHTQYQFSV 568
Cdd:cd00063     1 PSPPTNLRVTDVTSTsVTLSWTpPEDDGGPITGYVVEYREKG------SGDWKEVEVTPGSEtSYTLTGLKPGTEYEFRV 74

                          90
                  ....*....|....*
gi 119573142  569 LAQNKLGSGPFSEIV 583
Cdd:cd00063    75 RAVNGGGESPPSESV 89

Seventh immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the seventh immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  226 PPVIVVPPKNSTVNASQDVSLACHAEAYPANlTYSW---FQDNINVFHISRLQPRVRILVDGSLRLLATQPDDAGCYTCV 302
Cdd:cd20954     1 PPRWIVEPVDANVAAGQDVMLHCQADGFPTP-TVTWkkaTGSTPGEYKDLLYDPNVRILPNGTLVFGHVQKENEGHYLCE 79

                          90
                  ....*....|....*..
gi 119573142  303 PSNGLLHPPSASAYLTV 319
Cdd:cd20954    80 AKNGIGSGLSKVIFLKV 96

Immunoglobulin (Ig)-like domain of myotilin, palladin, and myopalladin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in myotilin, palladin, and myopalladin. Myotilin, palladin, and myopalladin function as scaffolds that regulate actin organization. Myotilin and myopalladin are most abundant in skeletal and cardiac muscle; palladin is ubiquitously expressed in the organs of developing vertebrates and plays a key role in cellular morphogenesis. The three family members each interact with specific molecular partners with all three binding to alpha-actinin; In addition, palladin also binds to vasodilator-stimulated phosphoprotein (VASP) and ezrin, myotilin binds to filamin and actin, and myopalladin also binds to nebulin and cardiac ankyrin repeat protein (CARP). This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  402 PAFIERPKEEYFQEvGRELLIPCSAQGDPPPVVSWTKVGRGLQGQAQ----VDSNS--SLILRPLTKEAHGHWECSASNA 475
Cdd:cd05744     1 PHFLQAPGDLEVQE-GRLCRFDCKVSGLPTPDLFWQLNGKPVRPDSAhkmlVRENGrhSLIIEPVTKRDAGIYTCIARNR 79

                          90
                  ....*....|..
gi 119573142  476 VARVATSTNVYV 487
Cdd:cd05744    80 AGENSFNAELVV 91

Fibronectin type III domain;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142   495 VTNVSVVAL-PKGANVSWEPGFDG-GYLQRFSVWYtplakRPDRMHHDWVSLAVPVGAAHLLVPGLQPHTQYQFSVLAQN 572
Cdd:pfam00041    3 PSNLTVTDVtSTSLTVSWTPPPDGnGPITGYEVEY-----RPKNSGEPWNEITVPGTTTSVTLTGLKPGTEYEVRVQAVN 77

                   ....*...
gi 119573142   573 KLGSGPFS 580
Cdd:pfam00041   78 GGGEGPPS 85

agrin-responsive first immunoglobulin-like domains (Ig1) of the MuSK ectodomain; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domains (Ig1) of the Muscle-specific kinase (MuSK). MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  142 PPAVLEVQELEPVTLRCVARGSPLPHVTWKLRGK--DLGQGQGQVQVQNGTLRIRRVERGSSGVYTCQASS-TEGSATHA 218
Cdd:cd20970     8 PSFTVTAREGENATFMCRAEGSPEPEISWTRNGNliIEFNTRYIVRENGTTLTIRNIRRSDMGIYLCIASNgVPGSVEKR 87

                  ....*
gi 119573142  219 TQLLV 223
Cdd:cd20970    88 ITLQV 92

Immunoglobulin domain; Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142   231 VPPKNSTVNASQDVSLACHAEAYPANLTYSWFQDN---INVFHISRLQPRVRILvdgSLRLLATQPDDAGCYTCVPSNGL 307
Cdd:pfam00047    1 SAPPTVTVLEGDSATLTCSASTGSPGPDVTWSKEGgtlIESLKVKHDNGRTTQS---SLLISNVTKEDAGTYTCVVNNPG 77

                   ....*
gi 119573142   308 LHPPS 312
Cdd:pfam00047   78 GSATL 82

Second Ig-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the titin Z1z2 lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142  135 PPQFQETPPAvLEVQELEPVTLRCVARGSPLPHVTWKLRGKDLGQGQGQVQVQNG---TLRIRRVERGSSGVYTCQASST 211
Cdd:cd20972     1 PPQFIQKLRS-QEVAEGSKVRLECRVTGNPTPVVRWFCEGKELQNSPDIQIHQEGdlhSLIIAEAFEEDTGRYSCLATNS 79

                          90
                  ....*....|..
gi 119573142  212 EGSATHATQLLV 223
Cdd:cd20972    80 VGSDTTSAEIFV 91

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 119573142    492 PHVVTNVSVVALPKG-ANVSWEPGFD---GGYLQRFSVWYTPLakrpdrmHHDWVSLAVPVGAAHLLVPGLQPHTQYQFS 567
Cdd:smart00060    1 PSPPSNLRVTDVTSTsVTLSWEPPPDdgiTGYIVGYRVEYREE-------GSEWKEVNVTPSSTSYTLTGLKPGTEYEFR 73

                            90
                    ....*....|
gi 119573142    568 VLAQNKLGSG 577
Cdd:smart00060   74 VRAVNGAGEG 83