EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958801356 304 FDTLLMAFRHYDKKGDGVIDRAELHEACVQANL--HLDKMLLDHLFDYCDVDQDGLINYLEFANFLT 368
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLEEgePLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958801356 304 FDTLLMAFRHYDKKGDGVIDRAELHEACVQANL--HLDKMLLDHLFDYCDVDQDGLINYLEFANFLT 368
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLEEgePLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958801356 292 ARHHLKKFNHQHFDTLLMAFRHYDKKGDGVIDRAELHEAcvQANLHLDKMLLDHLFDYCDVDQDGLINYLEFANFLT 368
Cdd:COG5126    56 VAGMESLFEATVEPFARAAFDLLDTDGDGKISADEFRRL--LTALGVSEEEADELFARLDTDGDGKISFEEFVAAVR 130

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958801356 304 FDTLLMAFRHYDKKGDGVIDRAELHEACVQANL--HLDKMLLDHLFDYCDVDQDGLINYLEFANFLT 368
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLEEgePLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958801356 292 ARHHLKKFNHQHFDTLLMAFRHYDKKGDGVIDRAELHEAcvQANLHLDKMLLDHLFDYCDVDQDGLINYLEFANFLT 368
Cdd:COG5126    56 VAGMESLFEATVEPFARAAFDLLDTDGDGKISADEFRRL--LTALGVSEEEADELFARLDTDGDGKISFEEFVAAVR 130

EF-hand domain pair;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1958801356 318 GDGVIDRAELHEACVQANL-HLDKMLLDHLFDYCDVDQDGLINYLEFANFLT 368
Cdd:pfam13833   1 EKGVITREELKRALALLGLkDLSEDEVDILFREFDTDGDGYISFDEFCVLLE 52

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 1958801356 311 FRHYDKKGDGVIDRAELHEACVQANLHLDKMLLDHLFDYCDVDQDGLINYLEFANFL 367
Cdd:cd15898     6 WIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELY 62

EF-hand, extracellular calcium-binding (EC) motif, found in secreted protein acidic and rich in cysteine (SPARC)-like proteins; The SPARC protein family represents a diverse group of proteins that share a follistatin-like (FS) domain and an extracellular calcium-binding (EC) domain with two EF-hand motifs. It includes SPARC (for secreted protein acidic and rich in cysteine, also termed osteonectin/ON, or basement-membrane protein 40/BM-40), SPARC-like protein 1 (for secreted protein, acidic and rich in cysteines-like 1/ SPARCL1, also termed high endothelial venule protein/Hevi, or MAST 9, or SC-1, or RAGS-1, or QR1, or ECM 2), testicans 1, 2, and 3 (also termed SPARC/osteonectin, CWCV, and Kazal-like domains proteoglycans, or SPOCK), secreted modular calcium-binding protein SMOC-1 (also termed SPARC-related modular calcium-binding protein 1) and SMOC-2 (also termed SPARC-related modular calcium-binding protein 2, or smooth muscle-associated protein 2/SMAP-2), follistatin-related protein 1 (FRP-1, also termed follistatin-like protein 1/fstl-1, TSC-36/Flik, TGF-beta inducible protein). The SPARC proteins have been implicated in modulating cell interaction with the extracellular milieu, including regulation of extracellular matrix assembly and deposition, counter-adhesion, effects on extracellular protease activity, and modulation of growth factor/cytokine signaling pathways, as well as in development and disease.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1958801356 311 FRHYDKKGDGVIDRAELheacvqANLHLDKMLLDH----LFDYCDVDQDGLINYLEFA 364
Cdd:cd00252    51 FDNLDNNKDGKLDKREL------APFRAPLMPLEHcargFFESCDLNKDKKISLQEWL 102

EF-hand, extracellular calcium-binding (EC) motif, found in testicans; Testicans are nervous system-expressed proteoglycans that play important roles in the regulation of protease activity, as well as in the determination of age at menarche. Testican-1 (TICN1, also termed protein SPOCK) is a secreted chimeric proteoglycan that is highly expressed in brain and carries both chondroitin and heparan sulfate glycosaminoglycan side chains. It has been implicated in autoimmune disease. It also acts as a regulator of bone morphogenetic protein (BMP) signaling and show critical functions in the nervous system. Testican-2 (TICN2, also termed protein SPOCK2) is an extracellular heparan sulphate proteoglycan highly expressed in brain. It may play regulatory roles in the development of the central nervous system. It also participates in diverse steps of neurogenesis. TICN1, but not TICN2, inhibits cathepsin L. TICN1 also inhibits attachment and neurite outgrowth in cultures of N2A neuroblastoma cells, While TICN2 is able to inhibit neurite outgrowth from primary cerebellar cells. Testicans contain an N-terminal signal peptide, a testican-specific domain followed by a follistatin-like (FS) domain, an extracellular calcium-binding (EC) domain including a pair of EF hands, a thyroglobulin-like domain (TY), and a C-terminal region with two putative glycosaminoglycan attachment sites. The substitution of a ligating Asp residue by Tyr orTyr in the +Y position of EF hand 2 in testican-2 could prevent Ca2+ binding to this site and also cause EF-hand 1 to bind one Ca2+ with low affinity. The substitution of a ligating Asp residue by Phe or Tyr in the +Y position of EF-hand 2 in testicans could prevent Ca2+ binding to this site and also cause EF-hand 1 to bind one Ca2+ ion with low affinity.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1958801356 311 FRHYDKKGDGVIDRAELheacvqANLHLDKM--LLDHLFDYCDVDQDGLIN 359
Cdd:cd16232    52 FNQLDTNNDLHLSQSEL------YDLELDKYepCIKPFLDSCDRNKDGKIS 96

EF-hand domain;

                          10        20
                  ....*....|....*....|....*
gi 1958801356 307 LLMAFRHYDKKGDGVIDRAELHEAC 331
Cdd:pfam13405   2 LREAFKLFDKDGDGKISLEELRKAL 26

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1958801356 310 AFRHYDKKGDGVIDRAEL----HEACVQANLHLDKMLLDHLFDYC----DVDQDGLINYLEFANFL 367
Cdd:cd15902    95 IWRKYDTDGSGFIEAKELkgflKDLLLKNKKHVSPPKLDEYTKLIlkefDANKDGKLELDEMAKLL 160