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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  15 EEFKEAFNLFDRNGDGNITTAELGTVMRslgqnpteADLADMINSIDTDGNGVISFVEFVRLMVTKSRNTDsEEELREAF 94
Cdd:COG5126    5 RKLDRRFDLLDADGDGVLERDDFEALFR--------RLWATLFSEADTDGDGRISREEFVAGMESLFEATV-EPFARAAF 75

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 159111176  95 RVFDRNGDGYVNAAELRHVLTHIGekLDEDEVDDLLREADIDGEGQIKYADFVKIL 150
Cdd:COG5126   76 DLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAV 129

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 159111176   87 EEELREAFRVFDRNGDGYVNAAELRHVLTHI--GEKLDEDEVDDLLREADIDGEGQIKYADFVKILC 151
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

XopAW family type III secretion system calcium-binding effector;

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  18 KEAFNLFDRNGDGNITTAELGTVMRS---LGQNPTEADLAD-MINSIDTDGNGVISFVEFVRLMVTKSRNTDSEEelreA 93
Cdd:NF041410  66 SELFSDLDSDGDGSLSSDELAAAAPPpppPPDQAPSTELADdLLSALDTDGDGSISSDELSAGLTSAGSSADSSQ----L 141

                         90
                 ....*....|....*..
gi 159111176  94 FRVFDRNGDGYVNAAEL 110
Cdd:NF041410 142 FSALDSDGDGSVSSDEL 158

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 159111176    16 EFKEAFNLFDRNGDGNITTAELGTVMRSL 44
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

centrin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176   7 INLPQETLEEFKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTDGNGVISFVEFVRLMVTKSRNTDS 86
Cdd:PTZ00183   9 PGLTEDQKKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFLDIMTKKLGERDP 88

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 159111176  87 EEELREAFRVFDRNGDGYVNAAELRHVLTHIGEKLDEDEVDDLLREADIDGEGQIKYADFVKIL 150
Cdd:PTZ00183  89 REEILKAFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRIM 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 159111176  16 EFKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTDGNGVISFVEFVRLM 77
Cdd:cd00051    1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELM 62

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 159111176  89 ELREAFRVFDRNGDGYVNAAELRHVLTHIGEKLDEDEVDDLLREADIDGEGQIKYADFVKIL 150
Cdd:cd00051    1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELM 62

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 159111176  17 FKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTDGNGVISFVEFVRLMVTKSRNtdseEELREAFRV 96
Cdd:cd15898    2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSLTER----PELEPIFKK 77

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 159111176  97 FDRNGDGYVNAAELRHVLTHI-GEKLDEDEVDDLLREADIDGE-GQIKYADFVKILC 151
Cdd:cd15898   78 YAGTNRDYMTLEEFIRFLREEqGENVSEEECEELIEKYEPEREnRQLSFEGFTNFLL 134

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 159111176  14 LEEFKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTDGNGVISFVEFVRLMVTKSRntdseeeLREA 93
Cdd:cd16180   66 IQDWRRLFRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACVTLKR-------LTDA 138

                         90
                 ....*....|...
gi 159111176  94 FRVFDRNGDGYVN 106
Cdd:cd16180  139 FRKYDTNRTGYAT 151

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 159111176  17 FKEAFNLFDRNGDGNITTAELGTVMRSL-----GQNPTEADLADMINSI----DTDGNGVISFVEFVRLMVTKSRN---- 83
Cdd:cd15902    1 FMEVWMHFDADGNGYIEGKELDSFLRELlkalnGKDKTDDEVAEKKKEFmekyDENEDGKIEIRELANILPTEENFlllf 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  84 -----TDSEEELREAFRVFDRNGDGYVNAAELRHVL--------THIGEKLDEDEVDDLLREADIDGEGQIKYADFVKIL 150
Cdd:cd15902   81 rreqpLISSVEFMKIWRKYDTDGSGFIEAKELKGFLkdlllknkKHVSPPKLDEYTKLILKEFDANKDGKLELDEMAKLL 160

centrin; Provisional

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 159111176  11 QETLEEFKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTDGNGVISFVEFVRLMVTKS 81
Cdd:PTZ00183  86 RDPREEILKAFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRIMKKTN 156

EF-hand, calcium binding motif, found in apoptosis-linked gene 2 protein (ALG-2) and similar proteins; ALG-2, also termed programmed cell death protein 6 (PDCD6), or probable calcium-binding protein ALG-2, is one of the prototypic members of the penta EF-hand protein family. It is a widely expressed calcium-binding modulator protein associated with cell proliferation and death, as well as cell survival. ALG-2 acts as a pro-apoptotic factor participating in T cell receptor-, Fas-, and glucocorticoid-induced programmed cell death, and also serves as a useful molecular marker for the prognosis of cancers. Moreover, ALG-2 functions as a calcium ion sensor at endoplasmic reticulum (ER) exit sites, and modulates ER-stress-stimulated cell death and neuronal apoptosis during organ formation. Furthermore, ALG-2 can mediate the pro-apoptotic activity of cisplatin or tumor necrosis factor alpha (TNFalpha) through the down-regulation of nuclear factor-kappaB (NF-kappaB) expression. It also inhibits angiogenesis through PI3K/mTOR/p70S6K pathway by interacting of vascular endothelial growth factor receptor-2 (VEGFR-2). In addition, nuclear ALG-2 may participate in the post-transcriptional regulation of Inositol Trisphosphate Receptor Type 1 (IP3R1) pre-mRNA at least in part by interacting with CHERP (Ca2+ homeostasis endoplasmic reticulum protein) calcium-dependently. ALG-2 contains five serially repeated EF-hand motifs and interacts with various proteins, including ALG-2-interacting protein X (Alix), Fas, annexin XI, death-associated protein kinase 1 (DAPk1), Tumor susceptibility gene 101 (TSG101), Sec31A, phospholipid scramblase 3 (PLSCR3), the P-body component PATL1, and endosomal sorting complex required for transport (ESCRT)-III-related protein IST1, in a calcium-dependent manner. 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.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  21 FNLFDRNGDGNITTAELGTVMrSLGQ----NPTEADLadMINSIDTDGNGVISFVEFVRL--MVTKSRNTdseeelreaF 94
Cdd:cd16183    6 FQRVDKDRSGQISATELQQAL-SNGTwtpfNPETVRL--MIGMFDRDNSGTINFQEFAALwkYITDWQNC---------F 73

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|...
gi 159111176  95 RVFDRNGDGYVNAAELRHVLTHIGEKLDEDEVDDLLREADIDGEGQIKYADFV 147
Cdd:cd16183   74 RSFDRDNSGNIDKNELKQALTSFGYRLSDQFYDILVRKFDRQGRGTIAFDDFI 126

Penta-EF hand, calcium binding motifs, found in PEF calpain family; The PEF calpain family belongs to the second group of penta-EF hand (PEF) proteins. It includes classical (also called conventional or typical) calpain (referring to a calcium-dependent papain-like enzymes, EC 3.4.22.17) large catalytic subunits (CAPN1, 2, 3, 8, 9, 11, 12, 13, 14) and two calpain small subunits (CAPNS1 and CAPNS2), which are largely confined to animals (metazoans). These PEF-containing are nonlysosomal intracellular calcium-activated intracellular cysteine proteases that play important roles in the degradation or functional modulation in a variety of substrates in response to calcium signalling. The classical mu- and m-calpains are heterodimers consisting of homologous but a distinct (large) L-subunit/chain (CAPN1 or CAPN2) and a common (small) S-subunit/chain (CAPNS1 or CAPNS2). These L-subunits (CAPN1 and CAPN2) and S-subunit CAPNS1 are ubiquitously found in all tissues. Other calpains likely consist of an isolated L-subunit/chain alone. Many of them, such as CAPNS2, CAPN3 (in skeletal muscle, or lens), CAPN8 (in stomach), CAPN9 (in digestive tracts), CAPN11 (in testis), CAPN12 (in follicles), are tissue-specific and have specific functions in distinct organs. The L-subunits of similar structure (called CALPA and B) also have been found in Drosophila melanogaster. The S-subunit seems to have a chaperone-like function for proper folding of the L-subunit. The catalytic L-subunits contain a short N-terminal anchor helix, followed by a calpain cysteine protease (CysPc) domain, a C2-domain-like (C2L) domain, and a C-terminal Ca2+-binding penta-EF-hand (PEF) domain. The S-subunits only have the PEF domain following an N-terminal Gly-rich hydrophobic domain. The calpains undergo a rearrangement of the protein backbone upon Ca2+-binding.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  56 MINSIDTDGNGVISFVEFVRLMVtksrntdSEEELREAFRVFDRNGDGYVNAAELRHVLTHIGEKLDEdEVDDLLREADI 135
Cdd:cd16182   47 LIALMDTNGSGRLDLEEFKTLWS-------DLKKWQAIFKKFDTDRSGTLSSYELRKALESAGFHLSN-KVLQALVLRYA 118

                         90
                 ....*....|....*..
gi 159111176 136 DGEGQIKYADFVKILCR 152
Cdd:cd16182  119 DSTGRITFEDFVSCLVR 135

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
                 ....*....|....*....|....*....|....*....|....*....
gi 159111176  15 EEFKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTD 63
Cdd:cd22949    3 EKFREAFILFDRDGDGELTMYEAVLAMRSCGIPLTNDEKDALPASMNWD 51

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 159111176  66 GVISFVEFVRLMVTKSRNTDSEEELREAFRVFDRNGDGYVNAAELRHVLTHIGEK-----LDEDEVDDLLREADIDGEGQ 140
Cdd:cd16252   15 GSFNYSKFFEYMQKFQTSEQQEEAIRKAFQMLDKDKSGFIEWNEIKYILSTVPSSmpvapLSDEEAEAMIQAADTDGDGR 94

                 ....*.
gi 159111176 141 IKYADF 146
Cdd:cd16252   95 IDFQEF 100

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 159111176  15 EEFKEAFNLFDRNGDGNITTAELGTVMRSL--GQNPTEAD--LADMINSI----DTDGNGVISFVEFVRLMVTK------ 80
Cdd:cd15902   90 VEFMKIWRKYDTDGSGFIEAKELKGFLKDLllKNKKHVSPpkLDEYTKLIlkefDANKDGKLELDEMAKLLPVQenfllk 169

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  81 ----SRNTDSEEELREAFRVFDRNGDGYVNAAELRHVLTHIGEKLDEDE--------VDDLLREADIDGEGQIKYADFVK 148
Cdd:cd15902  170 fqilGAMDLTKEDFEKVFEHYDKDNNGVIEGNELDALLKDLLEKNKADIdkpdlenfRDAILRACDKNKDGKIQKTELAL 249

                 ...
gi 159111176 149 ILC 151
Cdd:cd15902  250 FLS 252

EF-hand, calcium binding motif, found in reticulocalbin-3 (RCN-3); RCN-3, also termed EF-hand calcium-binding protein RLP49, is a putative six EF-hand Ca2+-binding protein that contains five RXXR (X is any amino acid) motifs and a C-terminal ER retrieval signal His-Asp-Glu-Leu (HDEL) tetrapeptide. The RXXR motif represents the target sequence of subtilisin-like proprotein convertases (SPCs). RCN-3 is specifically bound to the paired basic amino-acid-cleaving enzyme-4 (PACE4) precursor protein and plays an important role in the biosynthesis of PACE4.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  21 FNLFDRNGDGNITTAELGTVMrslgqNPTEAD------LADMINSIDTDGNGVISFVEFVRLMVTKSRNTDSE---EELR 91
Cdd:cd16230  129 FRVADQDGDSMATREELTAFL-----HPEEFPhmrdivVAETLEDLDKNKDGYVQVEEYIADLYSGEPGEEEPawvQTER 203

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 159111176  92 EAFRVF-DRNGDGYVNAAELRHVLTHIGEKLDEDEVDDLLREADIDGEGQIKYADFV 147
Cdd:cd16230  204 QQFRQFrDLNKDGRLDGSEVGHWVLPPSQDQPLVEANHLLHESDTDKDGRLSKAEIL 260

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
                 ....*....|....*....|....*....|....*....|....
gi 159111176  86 SEEELREAFRVFDRNGDGYVNAAELRHVLTHIGEKLDEDEVDDL 129
Cdd:cd22949    1 MEEKFREAFILFDRDGDGELTMYEAVLAMRSCGIPLTNDEKDAL 44

Penta-EF hand, calcium binding motifs, found in sorcin, grancalcin, and similar proteins; The family corresponds to the second group of penta-EF hand (PEF) proteins that includes sorcin, grancalcin, and similar proteins. Sorcin, also termed 22 kDa Ca2+-binding protein, CP-22, or V19, is a soluble resistance-related calcium-binding protein that is expressed in normal mammalian tissues, such as the liver, lungs and heart. It contains a flexible glycine and proline-rich N-terminal extension and five EF-hand motifs that associate with membranes in a calcium-dependent manner. It may harbor three potential Ca2+ binding sites through its EF1, EF2 and EF3 hands. However, binding of only two Ca2+/monomer suffices to trigger the conformational change that exposes hydrophobic regions and leads to interaction with the respective targets. Sorcin forms homodimers through the association of the unpaired EF5 hand. Among the PEF proteins, sorcin is unique in that it contains potential phosphorylation sites by cAMP-dependent protein kinase (PKA), and it can form a tetramer at slightly acid pH values although remaining a stable dimer at neutral pH. Grancalcin (GCA) is a cytosolic Ca2+-binding protein specifically expressed in neutrophils and monocytes/macrophages. It can strongly interact with sorcin to form a heterodimer and further modulate the function of sorcin. GCA exists as homodimers in solution. It contains five EF-hand motifs attached to an N-terminal region of an approximately 50 residue-long segment rich in glycines and prolines. In contrast with sorcin, GCA binds two Ca2+ ions through its EF1 and EF3 hands.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176   1 MEGDMPINLPQE---TLEEFKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEADLADMINSIDTdgNGVISFVEFVRLM 77
Cdd:cd16181   53 HSGKMGFNEFKElwaALNQWKTTFMQYDRDRSGTVEPQELQQAIRSFGYNLSPQALNVIVKRYSK--NGRITFDDFVACA 130

                         90       100
                 ....*....|....*....|....*....
gi 159111176  78 VtKSRntdseeELREAFRVFDRNGDGYVN 106
Cdd:cd16181  131 V-RLR------ALTDRFRRRDTQQNGTAT 152

EF-hand, calcium binding motif, found in calumenin, reticulocalbin-1 (RCN-1), reticulocalbin-3 (RCN-3), and similar proteins; The family corresponds to a group of six EF-hand Ca2+-binding proteins, including calumenin (also known as crocalbin or CBP-50), reticulocalbin-1 (RCN-1), reticulocalbin-3 (RCN-3), and similar proteins. Calumenin is an endo/sarcoplasmic reticulum (ER/SR) resident low-affinity Ca2+-binding protein that contains six EF-hand domains and a C-terminal SR retention signal His-Asp-Glu-Phe (HDEF) tetrapeptide. It functions as a novel regulator of SERCA2, and its expressional changes are tightly coupled with Ca2+-cycling of cardiomyocytes. It is also broadly involved in haemostasis and in the pathophysiology of thrombosis. Moreover, the extracellular calumenin acts as a suppressor of cell migration and tumor metastasis. RCN-1 is an endoplasmic reticulum resident Ca2+-binding protein with a carboxyl-terminal His-Asp-Glu-Leu (HDEL) tetrapeptide signal. It acts as a potential negative regulator of B-RAF activation and can negatively modulate cardiomyocyte hypertrophy by inhibition of the mitogen-activated protein kinase signalling cascade. It also plays a key role in the development of doxorubicin-associated resistance. RCN-3 is a putative six EF-hand Ca2+-binding protein that contains five RXXR (X is any amino acid) motifs and a C-terminal ER retrieval signal HDEL tetrapeptide. The RXXR motif represents the target sequence of subtilisin-like proprotein convertases (SPCs). RCN-3 is specifically bound to the paired basic amino-acid-cleaving enzyme-4 (PACE4) precursor protein and plays an important role in the biosynthesis of PACE4.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  18 KEAFNLFDRNGDGNITTAELGTVMrslgqNPTEAD------LADMINSIDTDGNGVISFVEFVRLMVTKSRNTDSEE--- 88
Cdd:cd16226  122 ERRWKAADQDGDGKLTKEEFTAFL-----HPEEFPhmrdivVQETLEDIDKNKDGFISLEEYIGDMYRDDDEEEDPDwvk 196

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 159111176  89 ELREAFRVF-DRNGDGYVNAAELRHVLTHIGEKLDEDEVDDLLREADIDGEGQI-------KYADFV 147
Cdd:cd16226  197 SEREQFKEFrDKNKDGKMDREEVKDWILPEDYDHAEAEAKHLIYEADDDKDGKLtkeeildKYDLFV 263

EF-hand domain;

                          10        20        30
                  ....*....|....*....|....*....|
gi 159111176   16 EFKEAFNLFDRNGDGNITTAELGTVMRSLG 45
Cdd:pfam13405   1 ELREAFKLFDKDGDGKISLEELRKALRSLG 30

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 159111176    89 ELREAFRVFDRNGDGYVNAAELRHVLTHI 117
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

EF hand; The EF-hands can be divided into two classes: signalling proteins and buffering/transport proteins. The first group is the largest and includes the most well-known members of the family such as calmodulin, troponin C and S100B. These proteins typically undergo a calcium-dependent conformational change which opens a target binding site. The latter group is represented by calbindin D9k and do not undergo calcium dependent conformational changes.

                          10        20
                  ....*....|....*....|....*....
gi 159111176   89 ELREAFRVFDRNGDGYVNAAELRHVLTHI 117
Cdd:pfam00036   1 ELKEIFRLFDKDGDGKIDFEEFKELLKKL 29

EF-hand domain pair;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 159111176   28 GDGNITTAELGTVMRSLG-QNPTEADLADMINSIDTDGNGVISFVEFVRLMV 78
Cdd:pfam13833   1 EKGVITREELKRALALLGlKDLSEDEVDILFREFDTDGDGYISFDEFCVLLE 52

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 159111176  17 FKEAFNLFDRNGDGNITTAELGTVMR------SLGQNPTEADLADMINS-IDT---------DGNGVISFVEFVRLMvtK 80
Cdd:cd15900    2 FEIAFKMFDLDGDGELDKEEFNKVQSiirsqtSVGQRHRDHTNGESTKLgMNStlaryffgkDGKQKLSIEKFLEFQ--E 79

                         90       100       110       120       130       140       150
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 159111176  81 SRNTDSeEELREAFRvFDRNGDGYVNAAELRHVL-THIGEKLDEDEVDDLLREADIDGEGQIKYADFVKILCRR 153
Cdd:cd15900   80 NLQEEI-DDVDTALT-FYHLAGASIDRKTFKRAAkVVAGVELSDHVVDVVFTIFDEDGDGILSHKEFISVMKDR 151

EF-hand, calcium binding motif, found in peflin and similar proteins; Peflin, also termed penta-EF hand (PEF) protein with a long N-terminal hydrophobic domain, or penta-EF hand domain-containing protein 1, 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+. In lower vertebrates, peflin may interact with transient receptor potential N (TRPN1), suggesting a potential role of peflin in fast transducer channel adaptation.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  21 FNLFDRNGDGNITTAEL-GTVMRSLGQNPTEADLADMINSIDTDGNGVISFVEFvrlmvtksrntdseEEL-------RE 92
Cdd:cd16184    6 FQAVDRDRSGKISAKELqQALVNGNWSHFNDETCRLMIGMFDKDKSGTIDIYEF--------------QALwnyiqqwKQ 71

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 159111176  93 AFRVFDRNGDGYVNAAELRHVLTHIGEKLDEDEVDDLLREADIDGEGQIKYADFVKI 149
Cdd:cd16184   72 VFQQFDRDRSGSIDENELHQALSQMGYRLSPQFVQFLVSKYDPRARRSLTLDQFIQV 128

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 159111176  56 MINSIDTDGNGVISFVEFVRLMvtksrntdseEELR---EAFRVFDRNGDGYVNAAELRHVLTHIGEKLDEDEVDDL-LR 131
Cdd:cd16196   46 MVAMMDVDRSGKLGFEEFKKLW----------EDLRswkRVFKLFDTDGSGSFSSFELRNALNSAGFRLSNATLNALvLR 115

                         90       100
                 ....*....|....*....|.
gi 159111176 132 EAdiDGEGQIKYADFVKILCR 152
Cdd:cd16196  116 YS--NKDGRISFDDFIMCAVK 134

EF hand; The EF-hands can be divided into two classes: signalling proteins and buffering/transport proteins. The first group is the largest and includes the most well-known members of the family such as calmodulin, troponin C and S100B. These proteins typically undergo a calcium-dependent conformational change which opens a target binding site. The latter group is represented by calbindin D9k and do not undergo calcium dependent conformational changes.

                          10        20
                  ....*....|....*....|....*....
gi 159111176   16 EFKEAFNLFDRNGDGNITTAELGTVMRSL 44
Cdd:pfam00036   1 ELKEIFRLFDKDGDGKIDFEEFKELLKKL 29

EF-hand, calcium binding motif, found in secretagogin (SCGN); 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 calcium sensor/coincidence detector modulating vesicular exocytosis of neurotransmitters, neuropeptides or hormones. It also serves as a calcium buffer in neurons. Thus, SCGN may be linked to the pathogenesis of neurological diseases such as Alzheimer's, and also acts as a serum marker of neuronal damage, or as a tumor biomarker. SCGN consists of the three globular domains each of which contains a pair of EF-hand motifs. All six EF hand motifs of SCGN in some eukaryotes, including D. rerio, X. laevis, M. domestica, G. gallus, O. anatinus, could potentially bind six calcium ions. In contrast, SCGNs from higher eukaryotes have at least one non-functional EF-hand motif due to the mutation(s) or deletions. For instance, the EF1 loop does not coordinate calcium ion due to the key residue asparagine replaced by lysine in SCGNs of many mammalian species. Moreover, the EF2 loop seems to be competent for calcium-binding in most mammalian SCGNs except for human and chimpanzee orthologs.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  17 FKEAFNLFDRNGDGNITTAELGTVMRSLGQN--PTEADLADMINSI--------DTDGNGVISFVEFVRLMVTKSRN--- 83
Cdd:cd16178    1 FAEIWQHFDADESGYIEGKELDNFFKDLLKKlgTKDTISADEVQDVkecfmsayDVTGDGRIQIQELANIILPDDENfll 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  84 -------TDSEEELREAFRVFDRNGDGYVNAAELRHVL----THIGEKLDEDEVDD----LLREADIDGEGQIKYADFVK 148
Cdd:cd16178   81 ffrreepLDSSVEFMRIWRKYDADSSGYISAAELKNFLrdlfLQHKKVITEDKLDEytdtMMKIFDKNKDGRLDLNDMAR 160

                 ..
gi 159111176 149 IL 150
Cdd:cd16178  161 IL 162

EF-hand, calcium binding motif, found in calbindin (CB); CB, also termed calbindin D28, or D-28K, or avian-type vitamin D-dependent calcium-binding protein, is a unique intracellular calcium binding protein that functions as both a calcium sensor and buffer in eukaryotic cells, which undergoes a conformational change upon calcium binding and protects cells against insults of high intracellular calcium concentration. CB is highly expressed in brain and sensory neurons. It plays essential roles in neural functioning, altering synaptic interactions in the hippocampus, modulating calcium channel activity, calcium transients, and intrinsic neuronal firing activity. It prevents a neuronal death, as well as maintains and controls calcium homeostasis. CB also modulates the activity of proteins participating in the development of neurodegenerative disorders such as Alzheimer's disease, Huntington's disease, and bipolar disorder. Moreover, CB interacts with Ran-binding protein M, a protein known to involve in microtubule function. It also interacts with alkaline phosphatase and myo-inositol monophosphatase, as well as caspase 3, an enzyme that plays an important role in the regulation of apoptosis. CB contains six EF-hand motifs in a single globular domain, where EF-hands 1, 3, 4, 5 bind four calcium ions with high affinity.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 159111176  17 FKEAFNLFDRNGDGNITTAELGTVMRSLGQNPTEA--DLAD----MINSIDTDGNGVISFVEFVRLMVTKS-------RN 83
Cdd:cd16176    1 FLEIWHHYDNDGNGYIEGKELQSFIQELQQARKKAglELSDqmkaFVDQYGQSTDGKIGIVELAQILPTEEnfllffrQQ 80