Ca2+-binding protein, EF-hand superfamily [Signal transduction mechanisms];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531   9 QISEFKEAFSLFDKDGDGCITTKELGTVMRslgqnpteAELQDMINEVDADGNGTIDFPEFLNLMARKMKDTDsEEELKE 88
Cdd:COG5126   3 QRRKLDRRFDLLDADGDGVLERDDFEALFR--------RLWATLFSEADTDGDGRISREEFVAGMESLFEATV-EPFARA 73

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 30688531  89 AFRVFDKDQNGFISAAELRHVMTNLGekLTDEEVDEMIKEADVDGDGQINYEEFVKVMM 147
Cdd:COG5126  74 AFDLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAVR 130

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 30688531    83 EEELKEAFRVFDKDQNGFISAAELRHVMTNL--GEKLTDEEVDEMIKEADVDGDGQINYEEFVKVMM 147
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

XopAW family type III secretion system calcium-binding effector;

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531    1 MADQLTDDQISEFKEAFSLFDKDGDGCITTKELGTVMRS----LGQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARK 76
Cdd:NF041410  53 LSSKSDDGSLIDLSELFSDLDSDGDGSLSSDELAAAAPPppppPDQAPSTELADDLLSALDTDGDGSISSDELSAGLTSA 132

                         90       100       110
                 ....*....|....*....|....*....|
gi 30688531   77 MKDTDSEeelkEAFRVFDKDQNGFISAAEL 106
Cdd:NF041410 133 GSSADSS----QLFSALDSDGDGSVSSDEL 158

Eps15 homology domain; Pair of EF hand motifs that recognise proteins containing Asn-Pro-Phe (NPF) sequences.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 30688531     82 SEEELK--EAFRVFDKDQNGFISAAELRHVMTNLGekLTDEEVDEMIKEADVDGDGQINYEEFVKVM 146
Cdd:smart00027   6 PEDKAKyeQIFRSLDKNQDGTVTGAQAKPILLKSG--LPQTLLAKIWNLADIDNDGELDKDEFALAM 70

centrin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531    4 QLTDDQISEFKEAFSLFDKDGDGCITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARKMKDTDSE 83
Cdd:PTZ00183  10 GLTEDQKKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFLDIMTKKLGERDPR 89

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 30688531   84 EELKEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMIKEADVDGDGQINYEEFVKVM 146
Cdd:PTZ00183  90 EEILKAFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRIM 152

EF-hand, calcium binding motif; A diverse superfamily of calcium sensors and calcium signal modulators; most examples in this alignment model have 2 active canonical EF hands. Ca2+ binding induces a conformational change in the EF-hand motif, leading to the activation or inactivation of target proteins. EF-hands tend to occur in pairs or higher copy numbers.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 30688531  85 ELKEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMIKEADVDGDGQINYEEFVKVMM 147
Cdd:cd00051   1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 63

Penta-EF hand, calcium binding motifs, found in Group I PEF proteins; The family corresponds to Group I PEF proteins that have been found not only in higher animals but also in lower animals, plants, fungi and protists. Group I PEF proteins include apoptosis-linked gene 2 protein (ALG-2), peflin and similar proteins. ALG-2, also termed programmed cell death protein 6 (PDCD6), is a widely expressed calcium-binding modulator protein associated with cell proliferation and death, as well as cell survival. It forms a homodimer in the cell or a heterodimer with its closest paralog peflin. Among the PEF proteins, ALG-2 can bind three Ca2+ ions through its EF1, EF3, and EF5 hands, where it is unique in that its EF5 hand binds Ca2+ ion in a canonical coordination. Peflin is a ubiquitously expressed 30-kD PEF protein containing five EF-hand motifs in its C-terminal domain and a longer N-terminal hydrophobic domain (NHB domain) than any other member of the PEF family. The NHB domain harbors nine repeats of a nonapeptide (A/PPGGPYGGP). Peflin may modulate the function of ALG-2 in Ca2+ signaling. It exists only as a heterodimer with ALG-2, and binds two Ca2+ ions through its EF1 and EF3 hands. Its additional EF5 hand is unpaired and does not bind Ca2+ ion but mediates the heterodimerization with ALG-2. The dissociation of heterodimer occurs in the presence of Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  12 EFKEAFSLFDKDGDGCITTKELGTVMRSLGQNPTEAE-LQDMINEVDADGNGTIDFPEFLNLMarkmkdtDSEEELKEAF 90
Cdd:cd16180   1 ELRRIFQAVDRDRSGRISAKELQRALSNGDWTPFSIEtVRLMINMFDRDRSGTINFDEFVGLW-------KYIQDWRRLF 73

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 30688531  91 RVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMIKEADVDGDGQINYEEFVKVMM 147
Cdd:cd16180  74 RRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACV 130

EF-hand, calcium binding motif, found in uncharacterized calglandulin-like proteins; The family corresponds to a group of uncharacterized calglandulin-like proteins. Although their biological function remain unclear, they show high sequence similarity with human calglandulin-like protein GAGLP, which is an ortholog of calglandulin from the venom glands of Bothrops insularis snake. Both GAGLP and calglandulin are putative Ca2+-binding proteins with four EF-hand motifs. However, members in this family contain only three EF-hand motifs. In this point, they may belong to the parvalbumin-like EF-hand family, which is characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  62 GTIDFPEFLNLMARKMKDTDSEEELKEAFRVFDKDQNGFISAAELRHVMTNLGEK-----LTDEEVDEMIKEADVDGDGQ 136
Cdd:cd16252  15 GSFNYSKFFEYMQKFQTSEQQEEAIRKAFQMLDKDKSGFIEWNEIKYILSTVPSSmpvapLSDEEAEAMIQAADTDGDGR 94

                ....*.
gi 30688531 137 INYEEF 142
Cdd:cd16252  95 IDFQEF 100

EF-hand, calcium binding motif, found in parvalbumin-like EF-hand family; The family includes alpha- and beta-parvalbumins, and a group of uncharacterized calglandulin-like proteins. Parvalbumins are small, acidic, cytosolic EF-hand-containing Ca2+-buffer and Ca2+ transporter/shuttle proteins belonging to EF-hand superfamily. They are expressed by vertebrates in fast-twitch muscle cells, specific neurons of the central and peripheral nervous system, sensory cells of the mammalian auditory organ (Corti's cell), and some other cells, and characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix) called AB, CD, and EF, but only CD and EF can chelate metal ions, such as Ca2+ and Mg2+. Thus, they may play an additional role in Mg2+ handling. Moreover, parvalbumins represent one of the major animal allergens. In metal-bound states, parvalbumins possess a rigid and stable tertiary structure and display strong allergenicity. In contrast, the metal-free parvalbumins are intrinsically disordered, and the loss of metal ions results in a conformational change that decreases their IgE binding capacity. Furthermore, parvalbumins have been widely used as a neuronal marker for a variety of functional brain systems. They also function as a Ca2+ shuttle transporting Ca2+ from troponin-C (TnC) to the sarcoplasmic reticulum (SR) Ca2+ pump during muscle relaxation. Thus they may facilitate myocardial relaxation and play important roles in cardiac diastolic dysfunction. Parvalbumins consists of alpha- and beta- sublineages, which can be distinguished on the basis of isoelectric point (pI > 5 for alpha; pI

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  62 GTIDFPEFLNLMARKMKdtdSEEELKEAFRVFDKDQNGFISAAELRHVMTNL---GEKLTDEEVDEMIKEADVDGDGQIN 138
Cdd:cd16251  15 GSFNYKKFFEHVGLKQK---SEDQIKKVFQILDKDKSGFIEEEELKYILKGFsiaGRDLTDEETKALLAAGDTDGDGKIG 91

                ....*.
gi 30688531 139 YEEFVK 144
Cdd:cd16251  92 VEEFAT 97

EF-hand motif found in eukaryotic phosphoinositide-specific phospholipase C (PI-PLC, EC 3.1.4.11) isozymes; PI-PLC isozymes are signaling enzymes that hydrolyze the membrane phospholipids phosphatidylinositol-4,5-bisphosphate (PIP2) to generate two important second messengers in eukaryotic signal transduction cascades, Inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol (DAG). InsP3 triggers inflow of calcium from intracellular stores, while DAG, together with calcium, activates protein kinase C, which goes on to phosphorylate other molecules, leading to altered cellular activity. Calcium is required for the catalysis. This family corresponds to the four EF-hand motifs containing PI-PLC isozymes, including PI-PLC-beta (1-4), -gamma (1-2), -delta (1,3,4), -epsilon (1), -zeta (1), eta (1-2). Lower eukaryotes such as yeast and slime molds contain only delta-type isozymes. In contrast, other types of isoforms present in higher eukaryotes. This family also includes 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase 1 (PLC1) from fungi. Some homologs from plants contain only two atypical EF-hand motifs and they are not included. All PI-PLC isozymes except sperm-specific PI-PLC-zeta share a core set of domains, including an N-terminal pleckstrin homology (PH) domain, four atypical EF-hand motifs, a PLC catalytic core, and a single C2 domain. PI-PLC-zeta lacks the PH domain. The PLC catalytic core domain is a TIM barrel with two highly conserved regions (X and Y) split by a highly degenerate linker sequence. Most of EF-hand motifs found in PI-PLCs consist of a helix-loop-helix structure, but lack residues critical to metal binding. Moreover, the EF-hand region of most of PI-PLCs may have an important regulatory function, but it has yet to be identified. However, PI-PLC-zeta is a key exception. It is responsible for Ca2+ oscillations in fertilized oocytes and exhibits a high sensitivity to Ca2+ mediated through its EF-hand domain. In addition, PI-PLC-eta2 shows a canonical EF-loop directing Ca2+-sensitivity and thus can amplify transient Ca2+ signals. Also it appears that PI-PLC-delta1 can regulate the binding of PH domain to PIP2 in a Ca2+-dependent manner through its functionally important EF-hand domains. PI-PLCs can be activated by a variety of extracellular ligands, such as growth factors, hormones, cytokines and lipids. Their activation has been implicated in tumorigenesis and/or metastasis linked to migration, proliferation, growth, inflammation, angiogenesis and actin cytoskeleton reorganization. PI-PLC-beta isozymes are activated by G-protein coupled receptor (GPCR) through different mechanisms. However, PI-PLC-gamma isozymes are activated by receptor tyrosine kinase (RTK), such as Rho and Ras GTPases. In contrast, PI-PLC-epsilon are activated by both GPCR and RTK. PI-PLC-delta1 and PLC-eta 1 are activated by GPCR-mediated calcium mobilization. The activation mechanism for PI-PLC-zeta remains unclear.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  13 FKEAFSLFDKDGDGCITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARKMkdtdSEEELKEAFRV 92
Cdd:cd15898   2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSLT----ERPELEPIFKK 77

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 30688531  93 FDKDQNGFISAAELRHVMTN-LGEKLTDEEVDEMIKEADVDG-DGQINYEEFVKVMM 147
Cdd:cd15898  78 YAGTNRDYMTLEEFIRFLREeQGENVSEEECEELIEKYEPEReNRQLSFEGFTNFLL 134

EF-hand, calcium binding motif, found in homologs of mammalian apoptosis-linked gene 2 protein (ALG-2); The family includes some homologs of mammalian apoptosis-linked gene 2 protein (ALG-2) mainly found in lower eukaryotes, such as a parasitic protist Leishmarua major and a cellular slime mold Dictyostelium discoideum. These homologs contains five EF-hand motifs. Due to the presence of unfavorable residues at the Ca2+-coordinating positions, their non-canonical EF4 and EF5 hands may not bind Ca2+. Two Dictyostelium PEF proteins are the prototypes of this family. They may bind to cytoskeletal proteins and/or signal-transducing proteins localized to detergent-resistant membranes named lipid rafts, and occur as monomers or weak homo- or heterodimers like ALG-2. They can serve as a mediator for Ca2+ signaling-related Dictyostehum programmed cell death (PCD).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  12 EFKEAFSLFDKDGDGCITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARKMKdtdseeeLKEAFR 91
Cdd:cd16185   1 ELRQWFRAVDRDRSGSIDVNELQKALAGGGLLFSLATAEKLIRMFDRDGNGTIDFEEFAALHQFLSN-------MQNGFE 73

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|..
gi 30688531  92 VFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMIKEADVDGDGQINYEEFV 143
Cdd:cd16185  74 QRDTSRSGRLDANEVHEALAASGFQLDPPAFQALFRKFDPDRGGSLGFDDYI 125

Ca2+-binding protein, EF-hand superfamily [Signal transduction mechanisms];

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 30688531   1 MADQLTDDQISEFKEAFSLFDKDGDGCITTKELGTVMRSLGqnPTEAELQDMINEVDADGNGTIDFPEFLNLMA 74
Cdd:COG5126  59 MESLFEATVEPFARAAFDLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAVR 130

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 30688531    10 ISEFKEAFSLFDKDGDGCITTKELGTVMRSL--GQNPTEAELQDMINEVDADGNGTIDFPEFLNLM 73
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELY 66

XopAW family type III secretion system calcium-binding effector;

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531    1 MADQLTDDQISEFKEAFSLFDKDGDGCITTKELGTVMRS----LGQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARK 76
Cdd:NF041410  53 LSSKSDDGSLIDLSELFSDLDSDGDGSLSSDELAAAAPPppppPDQAPSTELADDLLSALDTDGDGSISSDELSAGLTSA 132

                         90       100       110
                 ....*....|....*....|....*....|
gi 30688531   77 MKDTDSEeelkEAFRVFDKDQNGFISAAEL 106
Cdd:NF041410 133 GSSADSS----QLFSALDSDGDGSVSSDEL 158

EF-hand, calcium binding motif, found in beta-parvalbumin; Beta-parvalbumin, also termed Oncomodulin-1 (OM), is a small calcium-binding protein that is expressed in hepatomas, as well as in the blastocyst and the cytotrophoblasts of the placenta. It is also found to be expressed in the cochlear outer hair cells of the organ of Corti and frequently expressed in neoplasms. Mammalian beta-parvalbumin is secreted by activated macrophages and neutrophils. It may function as a tissue-specific Ca2+-dependent regulatory protein, and may also serve as a specialized cytosolic Ca2+ buffer. Beta-parvalbumin acts as a potent growth-promoting signal between the innate immune system and neurons in vivo. It has high and specific affinity for its receptor on retinal ganglion cells (RGC) and functions as the principal mediator of optic nerve regeneration. It exerts its effects in a cyclic adenosine monophosphate (cAMP)-dependent manner and can further elevate intracellular cAMP levels. Moreover, beta-parvalbumin is associated with efferent function and outer hair cell electromotility, and can identify different hair cell types in the mammalian inner ear. Beta-parvalbumin is characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix) called AB, CD, and EF, but only CD and EF can chelate metal ions, such as Ca2+ and Mg2+. The EF site displays a high-affinity for Ca2+/Mg2+, and the CD site is a low-affinity Ca2+-specific site. In addition, beta-parvalbumin is distinguished from other parvalbumins by its unusually low isoelectric point (pI = 3.1) and sequence eccentricities (e.g., Y57-L58-D59 instead of F57-I58-E59).

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  82 SEEELKEAFRVFDKDQNGFISAAELRHVMTNL---GEKLTDEEVDEMIKEADVDGDGQINYEEFVKVMMA 148
Cdd:cd16255  32 SADDVKKVFEIIDQDKSGFIEEEELKLFLQNFssgARELTDAETKAFLKAGDSDGDGKIGVEEFQALVKA 101

EF-hand, calcium binding motif; A diverse superfamily of calcium sensors and calcium signal modulators; most examples in this alignment model have 2 active canonical EF hands. Ca2+ binding induces a conformational change in the EF-hand motif, leading to the activation or inactivation of target proteins. EF-hands tend to occur in pairs or higher copy numbers.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 30688531  48 ELQDMINEVDADGNGTIDFPEFLNLMaRKMKDTDSEEELKEAFRVFDKDQNGFISAAELRHVMT 111
Cdd:cd00051   1 ELREAFRLFDKDGDGTISADELKAAL-KSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 63

EF-hand, calcium binding motif, found in mitochondrial calcium uptake proteins MICU1, MICU2, MICU3, and similar proteins; This family includes mitochondrial calcium uptake protein MICU1 and its two additional paralogs, MICU2 and MICU3. MICU1 localizes to the inner mitochondrial membrane (IMM). It functions as a gatekeeper of the mitochondrial calcium uniporter (MCU) and regulates MCU-mediated mitochondrial Ca2+ uptake, which is essential for maintaining mitochondrial homoeostasis. MICU1 and MICU2 are physically associated within the uniporter complex and are co-expressed across all tissues. They may play non-redundant roles in the regulation of the mitochondrial calcium uniporter. At present, the precise molecular function of MICU2 and MICU3 remain unclear. MICU2 may play possible roles in Ca2+ sensing and regulation of MCU, calcium buffering with a secondary impact on transport or assembly and stabilization of MCU. MICU3 likely has a role in mitochondrial calcium handling. All members in this family contains an N-terminal mitochondrial targeting sequence (MTS) as well as two evolutionarily conserved canonical Ca2+-binding EF-hands separated by a long stretch of residues predicted to form alpha-helices.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  13 FKEAFSLFDKDGDGCITTKELGTVMR------SLGQNPTEAELQDMINEVD----------ADGNGTIDFPEFLNLMARK 76
Cdd:cd15900   2 FEIAFKMFDLDGDGELDKEEFNKVQSiirsqtSVGQRHRDHTNGESTKLGMnstlaryffgKDGKQKLSIEKFLEFQENL 81

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 30688531  77 MKDTDseeELKEAFRvFDKDQNGFISAAELRHVM-TNLGEKLTDEEVDEMIKEADVDGDGQINYEEFVKVM 146
Cdd:cd15900  82 QEEID---DVDTALT-FYHLAGASIDRKTFKRAAkVVAGVELSDHVVDVVFTIFDEDGDGILSHKEFISVM 148

The penta-EF hand (PEF) family; The penta-EF hand (PEF) family contains a group of five EF-hand calcium-binding proteins, including several classical calpain large catalytic subunits (CAPN1, 2, 3, 8, 9, 11, 12, 13, 14), two calpain small subunits (CAPNS1 and CAPNS2), as well as non-calpain PEF proteins, ALG-2 (apoptosis-linked gene 2, also termed programmed cell death protein 6, PDCD6), peflin, sorcin, and grancalcin. Based on the sequence similarity of EF1 hand, ALG-2 and peflin have been classified into group I PEF proteins. Calcium-dependent protease calpain subfamily members, sorcin and grancalcin, are group II PEF proteins. Calpains (EC 3.4.22.17) are calcium-activated intracellular cysteine proteases that play important roles in the degradation or functional modulation in a variety of substrates. They have been implicated in a number of physiological processes such as cell cycle progression, remodeling of cytoskeletal-cell membrane attachments, signal transduction, gene expression and apoptosis. ALG-2 is a pro-apoptotic factor that forms a homodimer in the cell or a heterodimer with its closest paralog peflin through their EF5s. Peflin is a 30-kD PEF protein with a longer N-terminal hydrophobic domain than any other member of the PEF family, and it contains nine nonapeptide (A/PPGGPYGGP) repeats. It exists only as a heterodimer with ALG-2. The dissociation of heterodimer occurs in the presence of Ca2+. ALG-2 interacts with various proteins in a Ca2+-dependent manner. Sorcin (for soluble resistance-related calcium binding protein) is a soluble resistance-related calcium-binding protein that participates in the regulation of calcium homeostasis in cells. Grancalcin is a cytosolic Ca2+-binding protein specifically expressed in neutrophils and monocytes/macrophages. It plays a key role in leukocyte-specific functions that are responsible for host defense. Grancalcin can form a heterodimer together with sorcin. Members in this family contain five EF-hand motifs attached to an N-terminal region of variable length containing one or more short Gly/Pro-rich sequences. These proteins form homodimers or heterodimers through pairing between the 5th EF-hands from the two molecules. Unlike calmodulin, the PEF domains do not undergo major conformational changes upon binding Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  12 EFKEAFSLFDKDgDGCITTKELGTVMRSLGQNPTE-----AELQDMINEVDADGNGTIDFPEFLNLMArKMKDtdseeeL 86
Cdd:cd15897   1 QLRNVFQAVAGD-DGEISATELQQALSNVGWTHFDlgfslETCRSMIAMMDRDHSGKLNFSEFKGLWN-YIKA------W 72

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 30688531  87 KEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMIKEADvDGDGQINYEEFV 143
Cdd:cd15897  73 QEIFRTYDTDGSGTIDSNELRQALSGAGYRLSEQTYDIIIRRYD-RGRGNIDFDDFI 128

EF-hand, calcium binding motif, found in reticulocalbin-2 (RCN2) mainly from protostomes; This family corresponds to a group of uncharacterized RCN2-like proteins, which are mainly found in protostomes. Although their biological function remains unclear, they show high sequence similarity with RCN2 (also known as E6BP or TCBP-49), which is an endoplasmic reticulum resident low-affinity Ca2+-binding protein that has been implicated in immunity, redox homeostasis, cell cycle regulation and coagulation. Members in this family contain six copies of the EF-hand Ca2+-binding motif, but may lack a C-terminal His-Asp-Glu-Leu (HDEL) tetrapeptide that is required for retention of RCN2 in the endoplasmic reticulum (ER).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  10 ISEFKEAFSLFDKDGDGCITTKELgtvmrSLGQNPTE------AELQDMINEVDADGNGTIDFPEFLNLMArkmKDTDSE 83
Cdd:cd16227 121 LEDDKEMFEAADLNKDGKLDKTEF-----SAFQHPEEyphmhpVLIEQTLRDKDKDNDGFISFQEFLGDRA---GHEDKE 192

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 30688531  84 EEL--KEAF-RVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMIKEADVDGDGQINYEEFV 143
Cdd:cd16227 193 WLLveKDRFdEDYDKDGDGKLDGEEILSWLVPDNEEIAEEEVDHLFASADDDHDDRLSFDEIL 255

EF-hand, calcium binding motif, found in the hexa-EF hand proteins family; The hexa-EF hand proteins family, also named the calbindin sub-family, contains a group of six EF-hand Ca2+-binding proteins, including calretinin (CR, also termed 29 kDa calbindin), calbindin D28K (CB, also termed vitamin D-dependent calcium-binding protein, avian-type), and secretagogin (SCGN). CR is a cytosolic hexa-EF-hand calcium-binding protein predominantly expressed in a variety of normal and tumorigenic t-specific neurons of the central and peripheral nervous system. It is a multifunctional protein implicated in many biological processes, including cell proliferation, differentiation, and cell death. CB is highly expressed in brain tissue. It is a strong calcium-binding and buffering protein responsible for preventing a neuronal death as well as maintaining and controlling calcium homeostasis. SCGN is a six EF-hand calcium-binding protein expressed in neuroendocrine, pancreatic endocrine and retinal cells. It plays a crucial role in cell apoptosis, receptor signaling and differentiation. It is also involved in vesicle secretion through binding to various proteins, including interacts with SNAP25, SNAP23, DOC2alpha, ARFGAP2, rootletin, KIF5B, beta-tubulin, DDAH-2, ATP-synthase and myeloid leukemia factor 2. SCGN functions as a Ca2+ sensor/coincidence detector modulating vesicular exocytosis of neurotransmitters, neuropeptides or hormones. Although the family members share a significant amount of secondary sequence homology, they display altered structural and biochemical characteristics, and operate in distinct fashions. CB contains six EF-hand motifs in a single globular domain, where EF-hands 1, 3, 4, 5 bind four calcium ions. CR contains six EF-hand motifs within two independent domains, CR I-II and CR III-VI. They harbor two and four EF-hand motifs, respectively. The first 5 EF-hand motifs are capable of binding calcium ions, while the EF-hand 6 is inactive. SCGN consists of the three globular domains each of which contains a pair of EF-hand motifs. Human SCGN simultaneously binds four calcium ions through its EF-hands 3, 4, 5 and 6 in one high affinity and three low affinity calcium-binding sites. In contrast, SCGNs in other lower eukaryotes, such as D. rerio, X. laevis, M. domestica, G. gallus, O. anatinus, are fully competent in terms of six calcium-binding.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  12 EFKEAFSLFDKDGDGCITTKELGTVMRSL--------GQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARK------- 76
Cdd:cd15902  91 EFMKIWRKYDTDGSGFIEAKELKGFLKDLllknkkhvSPPKLDEYTKLILKEFDANKDGKLELDEMAKLLPVQenfllkf 170

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  77 ---MKDTDSEEELKEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDEE--------VDEMIKEADVDGDGQINYEEFVKV 145
Cdd:cd15902 171 qilGAMDLTKEDFEKVFEHYDKDNNGVIEGNELDALLKDLLEKNKADIdkpdlenfRDAILRACDKNKDGKIQKTELALF 250

                ....
gi 30688531 146 MMAK 149
Cdd:cd15902 251 LSAK 254

Penta-EF hand, calcium binding motifs, found in Group I PEF proteins; The family corresponds to Group I PEF proteins that have been found not only in higher animals but also in lower animals, plants, fungi and protists. Group I PEF proteins include apoptosis-linked gene 2 protein (ALG-2), peflin and similar proteins. ALG-2, also termed programmed cell death protein 6 (PDCD6), is a widely expressed calcium-binding modulator protein associated with cell proliferation and death, as well as cell survival. It forms a homodimer in the cell or a heterodimer with its closest paralog peflin. Among the PEF proteins, ALG-2 can bind three Ca2+ ions through its EF1, EF3, and EF5 hands, where it is unique in that its EF5 hand binds Ca2+ ion in a canonical coordination. Peflin is a ubiquitously expressed 30-kD PEF protein containing five EF-hand motifs in its C-terminal domain and a longer N-terminal hydrophobic domain (NHB domain) than any other member of the PEF family. The NHB domain harbors nine repeats of a nonapeptide (A/PPGGPYGGP). Peflin may modulate the function of ALG-2 in Ca2+ signaling. It exists only as a heterodimer with ALG-2, and binds two Ca2+ ions through its EF1 and EF3 hands. Its additional EF5 hand is unpaired and does not bind Ca2+ ion but mediates the heterodimerization with ALG-2. The dissociation of heterodimer occurs in the presence of Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  10 ISEFKEAFSLFDKDGDGCITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLNLMARKMKDTDseeelkeA 89
Cdd:cd16180  66 IQDWRRLFRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACVTLKRLTD-------A 138

                        90
                ....*....|..
gi 30688531  90 FRVFDKDQNGFI 101
Cdd:cd16180 139 FRKYDTNRTGYA 150

Penta-EF hand, calcium binding motifs, found in calpain-13 (CAPN13), calpain-14 (CAPN14), and similar proteins; CAPN13, also termed calcium-activated neutral proteinase 13 (CANP 13), a 63.6 kDa calpain large subunit that exhibits a restricted tissue distribution with low levels of expression detected only in human testis and lung. In calpain family, CAPN13 is most closely related to calpain-14 (CAPN14). CAPN14, also termed calcium-activated neutral proteinase 14 (CANP 14), is a 76.7 kDa calpain large subunit that is most highly expressed in the oesophagus. Its expression and calpain activity can be induced by IL-13. Both CAPN13 and CAPN14 contain a calpain cysteine protease (CysPc) domain, a C2-domain-like (C2L) domain, and a C-terminal Ca2+-binding penta-EF-hand (PEF) domain.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  52 MINEVDADGNGTIDFPEFLNLMaRKMKdtdseeELKEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEM-IKEAD 130
Cdd:cd16195  48 MVALMDLSVNGRLSLEEFSRLW-KKLR------KYKDIFQKADVSKSGFLSLSELRNAIQAAGIRVSDDLLNLMaLRYGD 120

                        90
                ....*....|....*..
gi 30688531 131 VdgDGQINYEEFVKVMM 147
Cdd:cd16195 121 S--SGRISFESFICLML 135

EF-hand domain pair;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 30688531    97 QNGFISAAELRHVMTNLGEK-LTDEEVDEMIKEADVDGDGQINYEEFVKVM 146
Cdd:pfam13833   1 EKGVITREELKRALALLGLKdLSEDEVDILFREFDTDGDGYISFDEFCVLL 51

Eps15 homology domain; found in proteins implicated in endocytosis, vesicle transport, and signal transduction. The alignment contains a pair of EF-hand motifs, typically one of them is canonical and binds to Ca2+, while the other may not bind to Ca2+. A hydrophobic binding pocket is formed by residues from both EF-hand motifs. The EH domain binds to proteins containing NPF (class I), [WF]W or SWG (class II), or H[TS]F (class III) sequence motifs.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  87 KEAFRVFDKDQNGFISAAELRHVMTNLGekLTDEEVDEMIKEADVDGDGQINYEEFVKVM 146
Cdd:cd00052   2 DQIFRSLDPDGDGLISGDEARPFLGKSG--LPRSVLAQIWDLADTDKDGKLDKEEFAIAM 59

EF-hand, calcium binding motif, found in parvalbumins; Parvalbumins are small, acidic, cytosolic EF-hand-containing Ca2+-buffer and Ca2+ transporter/shuttle proteins belonging to EF-hand superfamily. They are expressed by vertebrates in fast-twitch muscle cells, specific neurons of the central and peripheral nervous system, sensory cells of the mammalian auditory organ (Corti's cell), and some other cells, and characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix) called AB, CD, and EF, but only CD and EF can chelate metal ions, such as Ca2+ and Mg2+. Thus, they may play an additional role in Mg2+ handling. Moreover, parvalbumins represent one of the major animal allergens. In metal-bound states, parvalbumins possess a rigid and stable tertiary structure and display strong allergenicity. In contrast, the metal-free parvalbumins are intrinsically disordered, and the loss of metal ions results in a conformational change that decreases their IgE binding capacity. Furthermore, parvalbumins have been widely used as a neuronal marker for a variety of functional brain systems. They also function as a Ca2+ shuttle transporting Ca2+ from troponin-C (TnC) to the sarcoplasmic reticulum (SR) Ca2+ pump during muscle relaxation. Thus they may facilitate myocardial relaxation and play important roles in cardiac diastolic dysfunction. Parvalbumins consists of alpha- and beta- sublineages, which can be distinguished on the basis of isoelectric point (pI > 5 for alpha; pI

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 30688531  82 SEEELKEAFRVFDKDQNGFISAAELRHVMTNLGEK---LTDEEVDEMIKEADVDGDGQINYEEF 142
Cdd:cd16253  32 SPADIKKVFNILDQDKSGFIEEEELKLFLKNFSDGarvLSDKETKNFLAAGDSDGDGKIGVDEF 95

N-terminal domain of Myosin essential light chain ELC; ELC is part of the apicomplexan membrane-associated protein complex called the glideosome, which is essential for parasite motility. The glideosome is composed of six proteins: myosin A (MyoA), essential light chain ELC, myosin light chain MLC1 (also called MTIP), and the glideosome-associated proteins GAP40, GAP45, and GAP50. MyoA is a Class XIV myosin implicated in gliding motility, as well as host cell and tissue invasion by parasites. ELC binds to the MyoA neck region adjacent to the MLC1-binding site, and both myosin light chains co-located to the glideosome. Although ELCs bind to a conserved MyoA sequence, P. falciparum ELC adopts a distinct structure in the free and MyoA-bound state. Therefore ELCs enhance MyoA performance by inducing alpha helical structure formation in MyoA and thus stiffening its lever arm. It has been shown that disruption of MyoA, MLC1, or ELC have dramatic effects on parasite motility but do not affect parasite shape or replication. The ELC N-terminal domain is part of the EF-hand calcium binding motif superfamily. Calcium binding has no effect on the structure of ELCs.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 30688531  82 SEEELKEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDEEVDEMikeadvdgDGQINYEEFVKVMMAK 149
Cdd:cd22949   1 MEEKFREAFILFDRDGDGELTMYEAVLAMRSCGIPLTNDEKDAL--------PASMNWDQFENWAKKK 60

EF-hand domain;

                          10        20        30
                  ....*....|....*....|....*....|
gi 30688531    85 ELKEAFRVFDKDQNGFISAAELRHVMTNLG 114
Cdd:pfam13405   1 ELREAFKLFDKDGDGKISLEELRKALRSLG 30

Penta-EF hand, calcium binding motifs, found in Drosophila melanogaster calpain-A (CalpA), calpain-B (CalpB), and similar proteins; The family contains two calpains that have been found in Drosophila, CalpA and CalpB. CalpA, also termed calcium-activated neutral proteinase A (CANP A), or calpain-A catalytic subunit, is a Drosophila calpain homolog specifically expressed in a few neurons in the central nervous system, in scattered endocrine cells in the midgut, and in blood cells. CalpB, also termed calcium-activated neutral proteinase B (CANP B), contains calpain-B catalytic subunit 1 and calpain-B catalytic subunit 2. Both CalpA and CalpB are closely related to that of vertebrate calpains, and they share similar domain architecture, which consists of four domains: the N-terminal domain I, the catalytic domain II carrying the three active site residues, Cys, His and Asn, the Ca2+-regulated phospholipid-binding domain III, and penta-EF-hand Ca2+-binding domain IV. Besides, CalpA and CalpB display some distinguishing structural features that are not found in mammalian typical calpains. CalpA harbors a 76 amino acid long hydrophobic stretch inserted in domain IV, which may be involved in membrane attachment of this enzyme. CalpB has an unusually long N-terminal tail of 224 amino acids, which belongs to the class of intrinsically unstructured proteins (IUP) and may become ordered upon binding to target protein(s). Moreover, they do not need small regulatory subunits for their catalytic activity, and their proteolytic function is not regulated by an intrinsic inhibitor as the Drosophila genome contains neither regulatory subunit nor calpastatin orthologs. As a result, they may exist as a monomer or perhaps as a homo- or heterodimer together with a second large subunit. Furthermore, both CalpA and CalpB are dispensable for viability and fertility and do not share vital functions during Drosophila development. Phosphatidylinositol 4,5-diphosphate, phosphatidylinositol 4-monophosphate, phosphatidylinositol, and phosphatidic acid can stimulate the activity and the rate of activation of CalpA, but not CalpB. Calpain A modulates Toll responses by limited Cactus/IkappaB proteolysis. CalpB directly interacts with talin, an important component of the focal adhesion complex, and functions as an important modulator in border cell migration within egg chambers, which may act via the digestion of talin. CalpB can be phosphorylated by cAMP-dependent protein kinase (protein kinase A, PKA; EC 2.7.11.11) at Ser240 and Ser845, as well as by mitogen-activated protein kinase (ERK1 and ERK2; EC 2.7.11.24) at Thr747. The activation of the ERK pathway by extracellular signals results in the phosphorylation and activation of calpain B. In Schneider cells (S2), calpain B was mainly in the cytoplasm and upon a rise in Ca2+ the enzyme adhered to intracellular membranes.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  52 MINEVDADGNGTIDFPEFLNLMarkmkdtdseEEL---KEAFRVFDKDQNGFISAAELRHVMTNLGEKLTDeevdeMIKE 128
Cdd:cd16196  46 MVAMMDVDRSGKLGFEEFKKLW----------EDLrswKRVFKLFDTDGSGSFSSFELRNALNSAGFRLSN-----ATLN 110

                        90       100
                ....*....|....*....|...
gi 30688531 129 ADV----DGDGQINYEEFVKVMM 147
Cdd:cd16196 111 ALVlrysNKDGRISFDDFIMCAV 133

EF-hand, calcium binding motif; EF-hands are calcium-binding motifs that occur at least in pairs. Links between disease states and genes encoding EF-hands, particularly the S100 subclass, are emerging. Each motif consists of a 12 residue loop flanked on either side by a 12 residue alpha-helix. EF-hands undergo a conformational change unpon binding calcium ions.

                           10        20
                   ....*....|....*....|....*....
gi 30688531    121 EVDEMIKEADVDGDGQINYEEFVKVMMAK 149
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

The penta-EF hand (PEF) family; The penta-EF hand (PEF) family contains a group of five EF-hand calcium-binding proteins, including several classical calpain large catalytic subunits (CAPN1, 2, 3, 8, 9, 11, 12, 13, 14), two calpain small subunits (CAPNS1 and CAPNS2), as well as non-calpain PEF proteins, ALG-2 (apoptosis-linked gene 2, also termed programmed cell death protein 6, PDCD6), peflin, sorcin, and grancalcin. Based on the sequence similarity of EF1 hand, ALG-2 and peflin have been classified into group I PEF proteins. Calcium-dependent protease calpain subfamily members, sorcin and grancalcin, are group II PEF proteins. Calpains (EC 3.4.22.17) are calcium-activated intracellular cysteine proteases that play important roles in the degradation or functional modulation in a variety of substrates. They have been implicated in a number of physiological processes such as cell cycle progression, remodeling of cytoskeletal-cell membrane attachments, signal transduction, gene expression and apoptosis. ALG-2 is a pro-apoptotic factor that forms a homodimer in the cell or a heterodimer with its closest paralog peflin through their EF5s. Peflin is a 30-kD PEF protein with a longer N-terminal hydrophobic domain than any other member of the PEF family, and it contains nine nonapeptide (A/PPGGPYGGP) repeats. It exists only as a heterodimer with ALG-2. The dissociation of heterodimer occurs in the presence of Ca2+. ALG-2 interacts with various proteins in a Ca2+-dependent manner. Sorcin (for soluble resistance-related calcium binding protein) is a soluble resistance-related calcium-binding protein that participates in the regulation of calcium homeostasis in cells. Grancalcin is a cytosolic Ca2+-binding protein specifically expressed in neutrophils and monocytes/macrophages. It plays a key role in leukocyte-specific functions that are responsible for host defense. Grancalcin can form a heterodimer together with sorcin. Members in this family contain five EF-hand motifs attached to an N-terminal region of variable length containing one or more short Gly/Pro-rich sequences. These proteins form homodimers or heterodimers through pairing between the 5th EF-hands from the two molecules. Unlike calmodulin, the PEF domains do not undergo major conformational changes upon binding Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 30688531  10 ISEFKEAFSLFDKDGDGCITTKELGTVMRSLGQNPTEaELQDMINEVDADGNGTIDFPEFLNLMARKmkdtdseEELKEA 89
Cdd:cd15897  69 IKAWQEIFRTYDTDGSGTIDSNELRQALSGAGYRLSE-QTYDIIIRRYDRGRGNIDFDDFIQCCVRL-------QRLTDA 140

                        90
                ....*....|..
gi 30688531  90 FRVFDKDQNGFI 101
Cdd:cd15897 141 FRRYDKDQDGQI 152