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 1958669230 114 EIREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMTIL 175
Cdd:cd00051     1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELM 62

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230 107 ISVEELDEIREA-----FRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMTILGPKLVS 181
Cdd:COG5126    22 LERDDFEALFRRlwatlFSEADTDGDGRISREEFVAGMESLFEATVEPFARAAFDLLDTDGDGKISADEFRRLLTALGVS 101

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1958669230 182 SEgrdgflgnTIDSIFWQFDMQ---RVTLEELKHIL 214
Cdd:COG5126   102 EE--------EADELFARLDTDgdgKISFEEFVAAV 129

XopAW family type III secretion system calcium-binding effector;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230  91 LNRSLSAGSDSEQLANISveeldeirEAFRVLDRDGNGFISKQELGMAM-----RSLGYMPSEVELAIIMQrLDMDGDGQ 165
Cdd:NF041410   49 LSSALSSKSDDGSLIDLS--------ELFSDLDSDGDGSLSSDELAAAApppppPPDQAPSTELADDLLSA-LDTDGDGS 119

                          90
                  ....*....|
gi 1958669230 166 VDFDEFMTIL 175
Cdd:NF041410  120 ISSDELSAGL 129

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 1958669230 114 EIREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMTIL 175
Cdd:cd00051     1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELM 62

calmodulin; Provisional

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1958669230 113 DEIREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMTIL 175
Cdd:PTZ00184   84 EEIKEAFKVFDRDGNGFISAAELRHVMTNLGEKLTDEEVDEMIREADVDGDGQINYEEFVKMM 146

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230 107 ISVEELDEIREA-----FRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMTILGPKLVS 181
Cdd:COG5126    22 LERDDFEALFRRlwatlFSEADTDGDGRISREEFVAGMESLFEATVEPFARAAFDLLDTDGDGKISADEFRRLLTALGVS 101

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1958669230 182 SEgrdgflgnTIDSIFWQFDMQ---RVTLEELKHIL 214
Cdd:COG5126   102 EE--------EADELFARLDTDgdgKISFEEFVAAV 129

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 1958669230 113 DEIREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDgdgqvDFDEFMT 173
Cdd:cd22949     3 EKFREAFILFDRDGDGELTMYEAVLAMRSCGIPLTNDEKDALPASMNWD-----QFENWAK 58

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
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1958669230 116 REAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEF 171
Cdd:cd16183    70 QNCFRSFDRDNSGNIDKNELKQALTSFGYRLSDQFYDILVRKFDRQGRGTIAFDDF 125

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958669230 113 DEIREAFRVLDRDGNGFISKQELGMAM-------RSLgympSEVELAIIMQRLDMDGDGQVDFDEFMtilgpKLVSS 182
Cdd:cd16255    34 DDVKKVFEIIDQDKSGFIEEEELKLFLqnfssgaREL----TDAETKAFLKAGDSDGDGKIGVEEFQ-----ALVKA 101

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 1958669230  114 EIREAFRVLDRDGNGFISKQELGMAMRSL 142
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230 110 EELDEIREAFRVLDRDGNGFISKQEL-GMAMRSLGYMPSEvelaiimqrLDMDGDGQVDFDEFMTILGPklvsseGRDGF 188
Cdd:COG5126     2 LQRRKLDRRFDLLDADGDGVLERDDFeALFRRLWATLFSE---------ADTDGDGRISREEFVAGMES------LFEAT 66

                          90       100
                  ....*....|....*....|....*....
gi 1958669230 189 LGNTIDSIFWQFDM---QRVTLEELKHIL 214
Cdd:COG5126    67 VEPFARAAFDLLDTdgdGKISADEFRRLL 95

EF-hand domain;

                          10        20        30
                  ....*....|....*....|....*....|
gi 1958669230 114 EIREAFRVLDRDGNGFISKQELGMAMRSLG 143
Cdd:pfam13405   1 ELREAFKLFDKDGDGKISLEELRKALRSLG 30

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230  88 GNYLNRSLSAG------SDSEQLAN---------ISVEE-------LDEIREAFRVLDRDGNGFISKQELGMAMRSLGYM 145
Cdd:cd16185    19 VNELQKALAGGgllfslATAEKLIRmfdrdgngtIDFEEfaalhqfLSNMQNGFEQRDTSRSGRLDANEVHEALAASGFQ 98

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958669230 146 PSEVELAIIMQRLDMDGDGQVDFDEF--MTIlgpklvssegrdgFLGNTiDSIFWQFDMQR---VTL 207
Cdd:cd16185    99 LDPPAFQALFRKFDPDRGGSLGFDDYieLCI-------------FLASA-RNLFQAFDRQRtgrVTL 151

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230 112 LDEIREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMdgDGQVDFDEF 171
Cdd:cd16181    69 LNQWKTTFMQYDRDRSGTVEPQELQQAIRSFGYNLSPQALNVIVKRYSK--NGRITFDDF 126

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 1958669230 114 EIREAFRVLDRDGNGFISKQELGMAMRSL 142
Cdd:pfam00036   1 ELKEIFRLFDKDGDGKIDFEEFKELLKKL 29

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
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1958669230 118 AFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDmDGDGQVDFDEFMTIL 175
Cdd:cd16196    76 VFKLFDTDGSGSFSSFELRNALNSAGFRLSNATLNALVLRYS-NKDGRISFDDFIMCA 132

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 1958669230 115 IREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMTILGPKLVSSEgrdgflgntID 194
Cdd:cd15898     2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSLTERPE---------LE 72

                          90       100
                  ....*....|....*....|....*
gi 1958669230 195 SIFWQF---DMQRVTLEELKHILYH 216
Cdd:cd15898    73 PIFKKYagtNRDYMTLEEFIRFLRE 97

XopAW family type III secretion system calcium-binding effector;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230  91 LNRSLSAGSDSEQLANISveeldeirEAFRVLDRDGNGFISKQELGMAM-----RSLGYMPSEVELAIIMQrLDMDGDGQ 165
Cdd:NF041410   49 LSSALSSKSDDGSLIDLS--------ELFSDLDSDGDGSLSSDELAAAApppppPPDQAPSTELADDLLSA-LDTDGDGS 119

                          90
                  ....*....|
gi 1958669230 166 VDFDEFMTIL 175
Cdd:NF041410  120 ISSDELSAGL 129

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1958669230 113 DEIReaFRVLDRDGNGFISKQELGMAM--RSLGYMpSEVELAIIMQRLDMDGDGQVDFDEFM 172
Cdd:cd16226   121 DERR--WKAADQDGDGKLTKEEFTAFLhpEEFPHM-RDIVVQETLEDIDKNKDGFISLEEYI 179

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 1958669230  93 RSLSAGSDSEQLANISVEE-------LDEIREAFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLdMDGDGQ 165
Cdd:cd16182    45 RSLIALMDTNGSGRLDLEEfktlwsdLKKWQAIFKKFDTDRSGTLSSYELRKALESAGFHLSNKVLQALVLRY-ADSTGR 123

                  ....*..
gi 1958669230 166 VDFDEFM 172
Cdd:cd16182   124 ITFEDFV 130

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1958669230 107 ISVEEL-----------DEIREAFRVLDRDGNGFISKQELGMAMRS 141
Cdd:COG5126    86 ISADEFrrlltalgvseEEADELFARLDTDGDGKISFEEFVAAVRD 131

XopAW family type III secretion system calcium-binding effector;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230  94 SLSAGSDSEQLAnisvEELdeireaFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDMDGDGQVDFDEFMT 173
Cdd:NF041410   18 SSTSSARSQQFQ----KQL------FAKLDSDGDGSVSQDELSSALSSKSDDGSLIDLSELFSDLDSDGDGSLSSDELAA 87

                  ....
gi 1958669230 174 ILGP 177
Cdd:NF041410   88 AAPP 91

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

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1958669230  107 ISVEELDEIREAFRVLDRDGNGFISkqelGMAMRSLgYMPSEV---ELAIIMQRLDMDGDGQVDFDEF 171
Cdd:smart00027   4 ISPEDKAKYEQIFRSLDKNQDGTVT----GAQAKPI-LLKSGLpqtLLAKIWNLADIDNDGELDKDEF 66

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 1958669230 117 EAFRVLDRDGNGFISKQELGMAMRSL-----GYMPSEVELA----IIMQRLDMDGDGQVDFDEFMTILGP-----KLVSS 182
Cdd:cd15902     3 EVWMHFDADGNGYIEGKELDSFLRELlkalnGKDKTDDEVAekkkEFMEKYDENEDGKIEIRELANILPTeenflLLFRR 82

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 1958669230 183 EGRdgfLGNTID--SIFWQFDMQR---VTLEELKHILYHAF 218
Cdd:cd15902    83 EQP---LISSVEfmKIWRKYDTDGsgfIEAKELKGFLKDLL 120

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 1958669230 150 ELAIIMQRLDMDGDGQVDFDEFMTIL 175
Cdd:pfam00036   1 ELKEIFRLFDKDGDGKIDFEEFKELL 26

Penta-EF hand, calcium binding motifs, found in calcium-dependent protease small subunit CAPNS1 and CAPNS2; CAPNS1, also termed calpain small subunit 1 (CSS1), or calcium-activated neutral proteinase small subunit (CANP small subunit), or calcium-dependent protease small subunit (CDPS), or calpain regulatory subunit, is a common 28-kDa regulatory calpain subunit encoded by the calpain small 1 (Capns1, also known as Capn4) gene. It acts as a binding partner to form a heterodimer with the 80 kDa calpain large catalytic subunit and is required in maintaining the activity of calpain. CAPNS1 plays a significant role in tumor progression of human cancer, and functions as a potential therapeutic target in human hepatocellular carcinoma (HCC), nasopharyngeal carcinoma (NPC), glioma, and clear cell renal cell carcinoma (ccRCC). It may be involved in regulating migration and cell survival through binding to the SH3 domain of Ras GTPase-activating protein (RasGAP). It may also modulate Akt/FoxO3A signaling and apoptosis through PP2A. CAPNS1 contains an N-terminal glycine rich domain and a C-terminal PEF-hand domain. CAPNS2, also termed calpain small subunit 2 (CSS2), is a novel tissue-specific 30 kDa calpain small subunit that lacks two oligo-Gly stretches characteristic of the N-terminal Gly-rich domain of CAPNS1. CAPNS2 acts as a chaperone for the calpain large subunit, and appears to be the functional equivalent of CAPNS1. However, CAPNS2 binds the large subunit much more weakly than CAPNS1 and it does not undergo the autolytic conversion typical of CAPNS1.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230  93 RSLSAGSDSEQLANISVEEL----DEIRE---AFRVLDRDGNGFISKQELGMAMRSLGYMPSEVELAIIMQRLDmDGDGQ 165
Cdd:cd16188    46 RSMVAVMDSDTTGKLGFEEFkylwNNIKKwqgIYKQFDTDRSGTIGSQELPGAFEAAGFHLNEQLYQMIIRRYS-DEDGN 124

                          90
                  ....*....|
gi 1958669230 166 VDFDEFMTIL 175
Cdd:cd16188   125 MDFDNFISCL 134

EF-hand, calcium binding motif, found in calretinin (CR); CR, also termed 29 kDa calbindin, 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 possibly functions as a calcium buffer, calcium sensor, and apoptosis regulator, which may be implicated in many biological processes, including cell proliferation, differentiation, and cell death. CR contains six EF-hand motifs within two independent domains, CR I-II and CR III-VI. CR I-II consists of EF-hand motifs 1 and 2, and CR III-VI consists of EF-hand motifs 3-6. The first 5 EF-hand motifs are capable of binding calcium ions, while the EF-hand 6 is inactive. Thus, CR has two pairs of cooperative binding sites (I-II and III-IV), which display high affinity calcium-binding sites, and one independent calcium ion-binding site (V), which displays lower affinity binding.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958669230 117 EAFRVLDRDGNGFISK-------QELGMAMRSLGYMPSEVELAI----IMQRLDMDGDGQVDFDEFMTIL 175
Cdd:cd16177     3 EIWKHFDADGNGYIEGkelenffRELERARRGAGVDSKSANFGEkmkeFMQKYDKNADGRIEMAELAQIL 72

EF hand;

                          10        20
                  ....*....|....*....|....*
gi 1958669230 151 LAIIMQRLDMDGDGQVDFDEFMTIL 175
Cdd:pfam13202   1 LKDTFRQIDLNGDGKISKEELRRLL 25