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
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 1032816773  1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMA 58
Cdd:cd00051    6 FRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 63

EF-hand domain pair;

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 1032816773  1 FSLFDKDGDGQITTKELGTVMRSL--GQNPSESELQDMINEVDADNNGTIDFPEFLTMM 57
Cdd:pfam13499  8 FKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELY 66

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 1032816773  32 ELQDMINEVDADNNGTIDFPEFLTMMARK 60
Cdd:smart00054  1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

XopAW family type III secretion system calcium-binding effector;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1032816773  29 SESELQDMINEVDADNNGTIDFPEFLTMMARKmKDTDSEEEIREAFKVFDRDNNGFISAAE 89
Cdd:NF041410   25 SQQFQKQLFAKLDSDGDGSVSQDELSSALSSK-SDDGSLIDLSELFSDLDSDGDGSLSSDE 84

centrin; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMARKMKDTDSEEEIREAFKVFDRD 80
Cdd:PTZ00183   23 FDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFLDIMTKKLGERDPREEILKAFRLFDDD 102

                  ....*.
gi 1032816773  81 NNGFIS 86
Cdd:PTZ00183  103 KTGKIS 108

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLgqnpseseLQDMINEVDADNNGTIDFPEFLTMMARKMKDTDsEEEIREAFKVFDRD 80
Cdd:COG5126    11 FDLLDADGDGVLERDDFEALFRRL--------WATLFSEADTDGDGRISREEFVAGMESLFEATV-EPFARAAFDLLDTD 81

                  ....*....
gi 1032816773  81 NNGFISAAE 89
Cdd:COG5126    82 GDGKISADE 90

centrin; Provisional

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMARK 60
Cdd:PTZ00183   96 FRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRIMKKT 155

calmodulin; Provisional

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMARK 60
Cdd:PTZ00184   90 FKVFDRDGNGFISAAELRHVMTNLGEKLTDEEVDEMIREADVDGDGQINYEEFVKMMMSK 149

EF-hand domain pair;

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 1032816773  1 FSLFDKDGDGQITTKELGTVMRSL--GQNPSESELQDMINEVDADNNGTIDFPEFLTMM 57
Cdd:pfam13499  8 FKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELY 66

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMARKMkdtdSEEEIREAFKVFDRD 80
Cdd:cd15898     6 WIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSLT----ERPELEPIFKKYAGT 81

                  ....*....
gi 1032816773  81 NNGFISAAE 89
Cdd:cd15898    82 NRDYMTLEE 90

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESE-LQDMINEVDADNNGTIDFPEFLTMMarkmkdtDSEEEIREAFKVFDR 79
Cdd:cd16183     6 FQRVDKDRSGQISATELQQALSNGTWTPFNPEtVRLMIGMFDRDNSGTINFQEFAALW-------KYITDWQNCFRSFDR 78

                          90
                  ....*....|
gi 1032816773  80 DNNGFISAAE 89
Cdd:cd16183    79 DNSGNIDKNE 88

XopAW family type III secretion system calcium-binding effector;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1032816773   1 FSLFDKDGDGQITTKELGTVMRS----LGQNPSESELQDMINEVDADNNGTIDFPEFLTMMARKMKDTDSEeeirEAFKV 76
Cdd:NF041410   69 FSDLDSDGDGSLSSDELAAAAPPppppPDQAPSTELADDLLSALDTDGDGSISSDELSAGLTSAGSSADSS----QLFSA 144

                          90
                  ....*....|...
gi 1032816773  77 FDRDNNGFISAAE 89
Cdd:NF041410  145 LDSDGDGSVSSDE 157

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 1032816773  1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINevdadnngTIDFPEFLTMMARKMKDTD 65
Cdd:cd22949    9 FILFDRDGDGELTMYEAVLAMRSCGIPLTNDEKDALPA--------SMNWDQFENWAKKKLAYSD 65

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMARKMKDTDseeeireAFKVFDRD 80
Cdd:cd16180    73 FRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACVTLKRLTD-------AFRKYDTN 145

                  ....*
gi 1032816773  81 NNGFI 85
Cdd:cd16180   146 RTGYA 150

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSL-----GQNPSESELQDMINEV----DADNNGTIDFPEFLTMMA---------RKMK 62
Cdd:cd15902     5 WMHFDADGNGYIEGKELDSFLRELlkalnGKDKTDDEVAEKKKEFmekyDENEDGKIEIRELANILPteenflllfRREQ 84

                          90       100
                  ....*....|....*....|....*..
gi 1032816773  63 DTDSEEEIREAFKVFDRDNNGFISAAE 89
Cdd:cd15902    85 PLISSVEFMKIWRKYDTDGSGFIEAKE 111

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
                 ....*....|....*....|....
gi 1032816773 66 SEEEIREAFKVFDRDNNGFISAAE 89
Cdd:cd22949    1 MEEKFREAFILFDRDGDGELTMYE 24

XopAW family type III secretion system calcium-binding effector;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVDADNNGTIDFPEFLTMMA------RKMKDTDSEEEIreaF 74
Cdd:NF041410   33 FAKLDSDGDGSVSQDELSSALSSKSDDGSLIDLSELFSDLDSDGDGSLSSDELAAAAPppppppDQAPSTELADDL---L 109

                          90
                  ....*....|....*
gi 1032816773  75 KVFDRDNNGFISAAE 89
Cdd:NF041410  110 SALDTDGDGSISSDE 124

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 1032816773   2 SLFDK--DGDGQITTKELGTVMRSlgQNPSESELQD---------MINEVDADNNGTIDFPEFLTMMARKmkdtdseEEI 70
Cdd:cd16182     4 ELFEKlaGEDEEIDAVELQKLLNA--SLLKDMPKFDgfsletcrsLIALMDTNGSGRLDLEEFKTLWSDL-------KKW 74

                          90
                  ....*....|....*....
gi 1032816773  71 REAFKVFDRDNNGFISAAE 89
Cdd:cd16182    75 QAIFKKFDTDRSGTLSSYE 93

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
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1032816773  33 LQDMINEVDADNNGTIDFPEFLTMMaRKMKDTDSEEEIREAFKVFDRDNNGFISAAE 89
Cdd:cd15898     2 LRRQWIKADKDGDGKLSLKEIKKLL-KRLNIRVSEKELKKLFKEVDTNGDGTLTFDE 57

EF-hand domain;

                         10        20
                 ....*....|....*....|....*
gi 1032816773  1 FSLFDKDGDGQITTKELGTVMRSLG 25
Cdd:pfam13405  6 FKLFDKDGDGKISLEELRKALRSLG 30

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
                 ....*....|....*....|....*....|....*....|....*....|...
gi 1032816773  1 FSLFDKDGDGQITTKELGTVMRSLGQnpSESELQDMINEVDADNNGTIDFPEF 53
Cdd:cd00052    5 FRSLDPDGDGLISGDEARPFLGKSGL--PRSVLAQIWDLADTDKDGKLDKEEF 55

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSEsELQDMINEVDADNNGTIDFPEFLTMMARKmkdtdseEEIREAFKVFDRD 80
Cdd:cd15897    76 FRTYDTDGSGTIDSNELRQALSGAGYRLSE-QTYDIIIRRYDRGRGNIDFDDFIQCCVRL-------QRLTDAFRRYDKD 147

                  ....*
gi 1032816773  81 NNGFI 85
Cdd:cd15897   148 QDGQI 152

S-100: S-100 domain, which represents the largest family within the superfamily of proteins carrying the Ca-binding EF-hand motif. Note that this S-100 hierarchy contains only S-100 EF-hand domains, other EF-hands have been modeled separately. S100 proteins are expressed exclusively in vertebrates, and are implicated in intracellular and extracellular regulatory activities. Intracellularly, S100 proteins act as Ca-signaling or Ca-buffering proteins. The most unusual characteristic of certain S100 proteins is their occurrence in extracellular space, where they act in a cytokine-like manner through RAGE, the receptor for advanced glycation products. Structural data suggest that many S100 members exist within cells as homo- or heterodimers and even oligomers; oligomerization contributes to their functional diversification. Upon binding calcium, most S100 proteins change conformation to a more open structure exposing a hydrophobic cleft. This hydrophobic surface represents the interaction site of S100 proteins with their target proteins. There is experimental evidence showing that many S100 proteins have multiple binding partners with diverse mode of interaction with different targets. In addition to S100 proteins (such as S100A1,-3,-4,-6,-7,-10,-11,and -13), this group includes the ''fused'' gene family, a group of calcium binding S100-related proteins. The ''fused'' gene family includes multifunctional epidermal differentiation proteins - profilaggrin, trichohyalin, repetin, hornerin, and cornulin; functionally these proteins are associated with keratin intermediate filaments and partially crosslinked to the cell envelope. These ''fused'' gene proteins contain N-terminal sequence with two Ca-binding EF-hands motif, which may be associated with calcium signaling in epidermal cells and autoprocessing in a calcium-dependent manner. In contrast to S100 proteins, "fused" gene family proteins contain an extraordinary high number of almost perfect peptide repeats with regular array of polar and charged residues similar to many known cell envelope proteins.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 1032816773 14 TKELGTVMRSLGQNPSeseLQDMINEVDADNNGTIDFPEFLTMMAR 59
Cdd:cd00213   37 ETELPNFLKNQKDPEA---VDKIMKDLDVNKDGKVDFQEFLVLIGK 79

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSL 24
Cdd:smart00054  6 FRLFDKDGDGKIDFEEFKDLLKAL 29

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1032816773   1 FSLFDKDGDGQITTKE----LGTVMRSLGQNP-SESELQDMINEVDADNNGTIDFPEFLTM 56
Cdd:cd16252    43 FQMLDKDKSGFIEWNEikyiLSTVPSSMPVAPlSDEEAEAMIQAADTDGDGRIDFQEFSDM 103

EF-hand domain;

                         10        20
                 ....*....|....*....|.
gi 1032816773 69 EIREAFKVFDRDNNGFISAAE 89
Cdd:pfam13405  1 ELREAFKLFDKDGDGKISLEE 21

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 1032816773   1 FSLFDKDGDGQITTKELGTVMrslgqNPSESE------LQDMINEVDADNNGTIDFPEFLTMMARK---MKDTDSEEEIR 71
Cdd:cd16226   125 WKAADQDGDGKLTKEEFTAFL-----HPEEFPhmrdivVQETLEDIDKNKDGFISLEEYIGDMYRDddeEEDPDWVKSER 199

                          90
                  ....*....|....*....
gi 1032816773  72 EAFKVF-DRDNNGFISAAE 89
Cdd:cd16226   200 EQFKEFrDKNKDGKMDREE 218

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 1032816773   4 FDKDGDGQITTKELGTVMRSL----GQNPSESELQDMIN----EVDADNNGTIDFPEFLTMMARK----------MKDTD 65
Cdd:cd15902    99 YDTDGSGFIEAKELKGFLKDLllknKKHVSPPKLDEYTKlilkEFDANKDGKLELDEMAKLLPVQenfllkfqilGAMDL 178

                          90       100
                  ....*....|....*....|....
gi 1032816773  66 SEEEIREAFKVFDRDNNGFISAAE 89
Cdd:cd15902   179 TKEDFEKVFEHYDKDNNGVIEGNE 202

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 1032816773  69 EIREAFKVFDRDNNGFISAAE 89
Cdd:smart00054  1 ELKEAFRLFDKDGDGKIDFEE 21

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 1032816773   1 FSLFDKDgDGQITTKELGTVMRSLGQNPSESEL-----QDMINEVDADNNGTIDFPEFlTMMARKMKDtdseeeIREAFK 75
Cdd:cd15897     6 FQAVAGD-DGEISATELQQALSNVGWTHFDLGFsletcRSMIAMMDRDHSGKLNFSEF-KGLWNYIKA------WQEIFR 77

                          90
                  ....*....|....
gi 1032816773  76 VFDRDNNGFISAAE 89
Cdd:cd15897    78 TYDTDGSGTIDSNE 91

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 1032816773   4 FDKDGDGQITTKELGTVMRSLGQNPSES------ELQDMINEVDADNNGTIDFPE----------FLTMMARKMKdtdSE 67
Cdd:cd16176     8 YDNDGNGYIEGKELQSFIQELQQARKKAglelsdQMKAFVDQYGQSTDGKIGIVElaqilpteenFLLFFRQQLK---SS 84

                          90       100
                  ....*....|....*....|..
gi 1032816773  68 EEIREAFKVFDRDNNGFISAAE 89
Cdd:cd16176    85 EEFMQTWRKYDADHSGFIEADE 106

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
                  ....*....|....*....|....*....|....*....|....
gi 1032816773  46 GTIDFPEFLTMMARKMKdtdSEEEIREAFKVFDRDNNGFISAAE 89
Cdd:cd16251    15 GSFNYKKFFEHVGLKQK---SEDQIKKVFQILDKDKSGFIEEEE 55

EF-hand domain pair;

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 1032816773 45 NGTIDFPEFLTMMARKMKDTDSEEEIREAFKVFDRDNNGFISAAE 89
Cdd:pfam13833  2 KGVITREELKRALALLGLKDLSEDEVDILFREFDTDGDGYISFDE 46

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 1032816773   1 FSLFDKDGDGQITTKELGTVMRSLGQNPSESELQDMINEVdaDNNGTIDFPEFLTMMARKMKDTDseeeireAFKVFDRD 80
Cdd:cd16181    76 FMQYDRDRSGTVEPQELQQAIRSFGYNLSPQALNVIVKRY--SKNGRITFDDFVACAVRLRALTD-------RFRRRDTQ 146

                  ...
gi 1032816773  81 NNG 83
Cdd:cd16181   147 QNG 149