The EF hand is a helix–loop–helix

structural domain In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of s ...

or ''motif'' found in a large

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of calcium-binding

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca²⁺ ions are coordinated by ligands within the loop. The motif takes its name from traditional nomenclature used in describing the protein

parvalbumin Parvalbumin (PV) is a calcium-binding protein with low molecular weight (typically 9-11 kDa). In humans, it is encoded by the ''PVALB'' gene. It is not a member of the albumin family; it is named for its size (''parv-'', from Latin ''parvus'' smal ...

, which contains three such motifs and is probably involved in

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

relaxation via its calcium-binding activity. The EF-hand consists of two

alpha helices The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...

linked by a short loop region (usually about 12

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

s) that usually binds

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

ions. EF-hands also appear in each

of the

signaling protein In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

calmodulin Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bind ...

and in the muscle protein

troponin-C Troponin C is a protein which is part of the troponin complex. It contains four calcium-binding EF hands, although different isoforms may have fewer than four functional calcium-binding subdomains. It is a component of thin filaments, along wi ...

Calcium ion binding site

The calcium ion is coordinated in a pentagonal bipyramidal configuration. The six residues involved in the binding are in positions 1, 3, 5, 7, 9 and 12; these residues are denoted by X, Y, Z, -Y, -X and -Z. The invariant Glu or Asp at position 12 provides two oxygens for liganding calcium (bidentate ligand). The calcium ion is bound by both protein backbone atoms and by amino acid

side chain In organic chemistry and biochemistry, a side chain is a chemical group that is attached to a core part of the molecule called the "main chain" or backbone. The side chain is a hydrocarbon branching element of a molecule that is attached to a l ...

s, specifically those of the anionic amino acid residues

aspartate Aspartic acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins. Like all other amino acids, it contains an amino group and a carboxylic acid. Its α-amino group is in the pro ...

and

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

. These residues are negatively charged and will make a charge-interaction with the positively charged calcium ion. The EF hand motif was among the first structural motifs whose sequence requirements were analyzed in detail. Five of the loop residues bind calcium and thus have a strong preference for

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

-containing side chains, especially aspartate and glutamate. The sixth residue in the loop is necessarily

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid (carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinogeni ...

due to the conformational requirements of the backbone. The remaining residues are typically

hydrophobic In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, th ...

and form a

hydrophobic core The hydrophobic effect is the observed tendency of nonpolar substances to aggregate in an aqueous solution and exclude water molecules. The word hydrophobic literally means "water-fearing", and it describes the segregation of water and nonpolar ...

that binds and stabilizes the two helices. Upon binding to Ca²⁺, this motif may undergo conformational changes that enable Ca²⁺-regulated functions as seen in Ca²⁺ effectors such as

(CaM) and

troponin C Troponin C is a protein which is part of the troponin complex. It contains four calcium-binding EF hands, although different isoforms may have fewer than four functional calcium-binding subdomains. It is a component of thin filaments, along wit ...

(TnC) and Ca²⁺ buffers such as

calreticulin Calreticulin also known as calregulin, CRP55, CaBP3, calsequestrin-like protein, and endoplasmic reticulum resident protein 60 (ERp60) is a protein that in humans is encoded by the ''CALR'' gene. Calreticulin is a multifunctional soluble prote ...

and

calbindin D9k Calbindins are three different calcium-binding proteins: calbindin, calretinin and S100G. They were originally described as vitamin D-dependent calcium-binding proteins in the intestine and kidney in the chick and mammals. They are now classified ...

. While the majority of the known EF-hand calcium-binding proteins (CaBPs) contain paired EF-hand motifs, CaBPs with single EF hands have also been discovered in both bacteria and eukaryotes. In addition, "EF-hand-like motifs" have been found in a number of bacteria. Although the coordination properties remain similar with the canonical 29-residue helix–loop–helix EF-hand motif, the EF-hand-like motifs differ from EF-hands in that they contain deviations in the secondary structure of the flanking sequences and/or variation in the length of the Ca²⁺-coordinating loop. EF hands have very high selectivity for calcium. For example, the dissociation constant of alpha

for Ca²⁺ is ~1000 times lower than that for the similar ion Mg²⁺. This high selectivity is due to the relatively rigid coordination geometry, the presence of multiple charged amino acid side chains in the binding site, as well as the ion solvation properties.

Prediction

Pattern (motif signature) search is one of the most straightforward ways to predict continuous EF-hand Ca²⁺-binding sites in proteins. Based on the sequence alignment results of canonical EF-hand motifs, especially the conserved side chains directly involved in Ca²⁺ binding, a patter
PS50222
has been generated to predict canonical EF-hand sites. Prediction servers may be found in the external links section.

Classification

Since the delineation of the EF-hand motif in 1973, the family of EF-hand proteins has expanded to include at least 66 subfamilies thus far. EF-hand motifs are divided into two major structural groups: * Canonical EF-hands as seen in calmodulin (CaM) and the prokaryotic CaM-like protein calerythrin. The 12-residue canonical EF-hand loop binds Ca²⁺ mainly via sidechain carboxylates or carbonyls (loop sequence positions 1, 3, 5, 12). The residue at the –X axis coordinates the Ca²⁺ ion through a bridged water molecule. The EF-hand loop has a bidentate ligand (Glu or Asp) at axis –Z. * Pseudo EF-hands exclusively found in the N-termini of S100 and S100-like proteins. The 14-residue pseudo EF-hand loop chelates Ca²⁺ primarily via backbone carbonyls (positions 1, 4, 6, 9). Additional points: * EF-hand-like proteins with diversified flanking structural elements around the Ca²⁺-binding loop have been reported in bacteria and viruses. These prokaryotic EF-hand-like proteins are widely implicated in Ca²⁺ signaling and homeostasis in bacteria. They contain flexible lengths of Ca²⁺-binding loops that differ from the EF-hand motifs. However, their coordination properties resemble classical EF-hand motifs. ** For example, the semi-continuous Ca²⁺-binding site in D-galactose-binding protein (GBP) contains a nine-residue loop. The Ca²⁺ ion is coordinated by seven protein oxygen atoms, five of which are from the loop mimicking the canonical EF-loop whereas the other two are from the carboxylate group of a distant Glu. ** Another example is a novel domain named Excalibur (extracellular Ca²⁺-binding region) isolated from ''

Bacillus subtilis ''Bacillus subtilis'', known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus ''Bacillu ...

''. This domain has a conserved 10-residue Ca²⁺-binding loop strikingly similar to the canonical 12-residue EF-hand loop. ** The diversity of the structure of the flanking region is illustrated by the discovery of EF-hand-like domains in bacterial proteins. For example, a helix–loop–strand instead of the helix–loop–helix structure is in periplasmic galactose-binding protein (''

Salmonella typhimurium ''Salmonella enterica'' subsp. ''enterica'' is a subspecies of ''Salmonella enterica'', the rod-shaped, flagellated, aerobic, Gram-negative bacterium. Many of the pathogenic serovars of the ''S. enterica'' species are in this subspecies, includi ...

'', ) or alginate-binding protein (''

Sphingomonas ''Sphingomonas'' was defined in 1990 as a group of Gram-negative, rod-shaped, chemoheterotrophic, strictly aerobic bacteria. They possess ubiquinone 10 as their major respiratory quinone, contain glycosphingolipids (GSLs), specifically ceramide ...

sp''., ); the entering helix is missing in protective antigen (''

Bacillus anthracis ''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent ( obligate) pathogen within the genus ''Bacillus''. Its infection is a ...

'', ) or dockerin (''

Clostridium thermocellum ''Acetivibrio thermocellus'' is an anaerobic, thermophilic bacterium. ''A. thermocellusm'' has garnered research interest due to its cellulolytic and ethanologenic abilities, being capable of directly converting a cellulosic substrate into etha ...

'', ). Among all the structures reported to date, the majority of EF-hand motifs are paired either between two canonical or one pseudo and one canonical motifs. For proteins with odd numbers of EF-hands, such as the penta-EF-hand calpain, EF-hand motifs were coupled through homo- or hetero-dimerization. The recently-identified EF-hand containing ER Ca²⁺ sensor protein, stromal interaction molecule 1 and 2 (STIM1, STIM2), has been shown to contain a Ca²⁺-binding canonical EF-hand motif that pairs with an immediate, downstream atypical "hidden" non-Ca²⁺-binding EF-hand. Single EF-hand motifs can serve as protein-docking modules: for example, the single EF hand in the NKD1 and NKD2 proteins binds the Dishevelled (DVL1, DVL2, DVL3) proteins. Functionally, the EF-hands can be divided into two classes: #signaling proteins #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 these proteins do not undergo calcium dependent conformational changes.

Subfamilies

* EPS15 homology (EH) domain –

Examples

Aequorin

Aequorin Aequorin is a calcium-activated photoprotein isolated from the hydrozoan ''Aequorea victoria''. Its bioluminescence was studied decades before the protein was isolated from the animal by Osamu Shimomura in 1962. In the animal, the protein occur ...

is a calcium binding protein (CaBP) isolated from the cnidarian ''

Aequorea victoria ''Aequorea victoria'', also sometimes called the crystal jelly, is a bioluminescent hydrozoan jellyfish, or hydromedusa, that is found off the west coast of North America. The species is best known as the source of two proteins involved in biolu ...

''. Aequorin belongs to the EF-hand family of CaBPs, with EF-hand loops that are closely related to CaBPs in mammals. In addition, aequorin has been used for years as an indicator of Ca²⁺ and has been shown to be safe and well tolerated by cells. Aequorin is made up of two components – the calcium binding component apoaequorin (AQ) and the chemiluminescent molecule

coelenterazine Coelenterazine is a luciferin, a molecule that emits light after reaction with oxygen, found in many aquatic organisms across eight phyla. It is the substrate of many luciferases such as ''Renilla reniformis'' luciferase (Rluc), ''Gaussia'' lucif ...

. The AQ portion of this protein contains the EF-hand calcium binding domains.

Human proteins

Humans proteins containing this domain include: *

ACTN1 Alpha-actinin-1 is a protein that in humans is encoded by the ''ACTN1'' gene. Function Alpha actinins belong to the spectrin gene superfamily which represents a diverse group of cytoskeletal proteins, including the alpha and beta spectrins an ...

;

ACTN2 Alpha-actinin-2 is a protein which in humans is encoded by the ''ACTN2'' gene. This gene encodes an alpha-actinin isoform that is expressed in both skeletal and cardiac muscles and functions to anchor myofibrillar actin thin filaments and titin to ...

;

ACTN3 Alpha-actinin-3, also known as alpha-actinin skeletal muscle isoform 3 or F-actin cross-linking protein, is a protein that in humans is encoded by the ''ACTN3'' gene (named sprinter gene, speed gene or athlete gene) located on chromosome 11. All ...

;

ACTN4 Alpha-actinin-4 is a protein that in humans is encoded by the ''ACTN4'' gene. Alpha actinins belong to the spectrin gene superfamily which represents a diverse group of cytoskeletal proteins, including the alpha and beta spectrins and dystrophins ...

; APBA2BP; AYTL1; AYTL2 * C14orf143; CABP1;

CABP2 Frozen state pensions is the practice of the British Government of "freezing" UK State Pensions, (that is, not uprating the amount in line with "Triple Lock" on an annual basis, as is done for residents in the UK), for pensioners who live in the ...

; CABP3; CABP4; CABP5; CABP7; CALB1;

CALB2 Calretinin, also known as calbindin 2 (formerly 29 kDa calbindin), is a calcium-binding protein involved in calcium signaling. In humans, the calretinin protein is encoded by the ''CALB2'' gene. Function This gene encodes an intracellular ca ...

;

CALM2 Calmodulin 2 is a protein that in humans is encoded by the ''CALM2'' gene. Clinical significance Mutations in CALM2 are associated to cardiac arrhythmias. Interactions CALM2 has been shown to interact with AKAP9. See also * calmodulin ...

;

CALM3 Calmodulin 3 is a protein that in humans is encoded by the ''CALM3'' gene. CALM-3 is best known for contracting the heart muscles, and depending on whether this activity is consistent or not, other diseases could emerge as a downside. It is able ...

;

CALML3 Calmodulin-like protein 3 is a protein that in humans is encoded by the ''CALML3'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' ...

; CALML4;

CALML5 Calmodulin-like protein 5 is a protein that in humans is encoded by the ''CALML5'' gene. This gene encodes a novel calcium binding protein expressed in the epidermis and related to the calmodulin family of calcium binding proteins. Functional ...

; CALML6; CALN1;

CALU Calu is an Etruscan chthonic deity, often equated with the Etruscan equivalent to the Greek Hades, Aita. He is identified by his wolf attributes, such as a wolf-like appearance or a human with a wolf-skin cap. The visual representations of the cul ...

;

CAPN1 Calpain-1 catalytic subunit (CANP 1) is a protein that in humans is encoded by the ''CAPN1'' gene. Function The calpains, calcium-activated neutral proteases, are nonlysosomal, intracellular cysteine proteases. The mammalian calpains include ...

; CAPN11;

CAPN2 Calpain-2 catalytic subunit is a protein that in humans is encoded by the ''CAPN2'' gene. Function The calpains, calcium-activated neutral proteases, are nonlysosomal, intracellular cysteine proteases. The mammalian calpains include ubiquitous ...

;

CAPN3 Calpain-3 is a protein that in humans is encoded by the ''CAPN3'' gene. Function Calpain, a heterodimer consisting of a large and a small subunit, is a major intracellular protease, although its function has not been well established. This gene ...

; CAPN9;

CAPNS1 Calpain small subunit 1 (CSS1), is a protein that in humans is encoded by the ''CAPNS1'' gene. Function Calpains are a ubiquitous, well-conserved family of calcium-dependent, cysteine proteases. Calpain families have been implicated in neurode ...

; CAPNS2;

CAPS Caps are flat headgear. Caps or CAPS may also refer to: Science and technology Computing * CESG Assisted Products Service, provided by the U.K. Government Communications Headquarters * Composite Application Platform Suite, by Java Caps, a Java ...

; CAPS2;

CAPSL CaPSL is a Printer Command Language, printer command language/page description language used by early Canon Inc., Canon printers including the LBP-8III series and supported on (at least) LBP-8IV printers. CaPSL was discontinued, with later Cano ...

; CBARA1;

CETN1 Centrin-1 is a protein that in humans is encoded by the ''CETN1'' gene. It belongs to the centrin Centrins, also known as caltractins, are a family of calcium-binding phosphoproteins found in the centrosome of eukaryotes. Centrins are present in ...

;

CETN2 Centrin-2 is a protein that in humans is encoded by the ''CETN2'' gene. It belongs to the centrin family of proteins. Centrin-2 belongs to a family of calcium-binding proteins and is a structural component of the centrosome. The high level of co ...

;

CETN3 Centrin-3 is a protein that in humans is encoded by the ''CETN3'' gene. It belongs to the centrin Centrins, also known as caltractins, are a family of calcium-binding phosphoproteins found in the centrosome of eukaryotes. Centrins are present i ...

; CHP;

CHP2 Belwood (Heurisko Pond) Water Aerodrome is located on Heurisko Pond, southwest of Belwood Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but i ...

;

CIB1 Calcium and integrin-binding protein 1 is a protein that in humans is encoded by the ''CIB1'' gene. The protein encoded by this gene is a member of the calcium-binding protein family. The specific function of this protein has not yet been determ ...

; CIB2; CIB3; CIB4; CRNN *

DGKA Diacylglycerol kinase alpha is an enzyme that in humans is encoded by the ''DGKA'' gene. The protein encoded by this gene belongs to the eukaryotic diacylglycerol kinase family. It acts as a modulator that competes with protein kinase C for the se ...

;

DGKB Diacylglycerol kinase beta is an enzyme that in humans is encoded by the ''DGKB'' gene. Function Diacylglycerol kinases (DGKs) are regulators of the intracellular concentration of the second messenger diacylglycerol A diglyceride, or diacyl ...

;

DGKG Diacylglycerol kinase gamma is an enzyme that in humans is encoded by the ''DGKG'' gene. This gene encodes an enzyme that is a member of the type I subfamily of diacylglycerol kinases, which are involved in lipid metabolism. These enzymes generate ...

;

DST Daylight saving time (DST), also referred to as daylight savings time or simply daylight time (United States, Canada, and Australia), and summer time (United Kingdom, European Union, and others), is the practice of advancing clocks (typicall ...

; DUOX1; DUOX2 * EFCAB1; EFCAB2; EFCAB4A; EFCAB4B; EFCAB6; EFCBP1; EFCBP2; EFHA1; EFHA2; EFHB; EFHC1; EFHD1; EFHD2;

EPS15 Epidermal growth factor receptor substrate 15 is a protein that in humans is encoded by the ''EPS15'' gene. Function This gene encodes a protein that is part of the EGFR pathway. The protein is present at clathrin-coated pits and is involved i ...

; EPS15L1 *

FKBP10 FK506-binding protein 10 is a protein that in humans is encoded by the ''FKBP10'' gene. The protein encoded by this gene belongs to the FKBP-type peptidyl-prolyl cis/trans isomerase family. It is located in endoplasmic reticulum and acts as mol ...

;

FKBP14 FKBP14 is a gene which codes for a structural protein named FKBP prolyl isomerase 14. This protein is believed to aid in the process of procollagen folding and is located in the endoplasmic reticulum that functions to process and transport proteins ...

; FKBP7; FKBP9; FKBP9L; FREQ; FSTL1; FSTL5 * GCA;

GPD2 GPD may refer to: Police departments * Gaithersburg Police Department, Maryland, United States * Gatlinburg Police Department, Tennessee, United States * Gladstone Police Department, Oregon, United States * Greenbelt Police Department (Maryland), ...

;

GUCA1A Guanylyl cyclase-activating protein 1 is an enzyme that in humans is encoded by the ''GUCA1A'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''g ...

; GUCA1B; GUCA1C *

hippocalcin Hippocalcin is a protein that in humans is encoded by the ''HPCA'' gene. Hippocalcin is a calcium-binding protein that belongs to the neuronal calcium sensor (NCS) family of proteins. It is expressed in mammalian brains especially in the hippoc ...

;

HPCAL1 Hippocalcin-like protein 1 is a protein that in humans is encoded by the ''HPCAL1'' gene. The protein encoded by this gene is a member of the neuron-specific calcium-binding proteins family found in the retina and brain. It is highly similar to h ...

; HPCAL4; HZGJ *

IFPS IFPS (Interactive Financial Planning System) was a financial modeling language created by professor Gerald R. Wagner and his students of the University of Texas at Austin in the late 1970s. IFPS was marketed by Execucom, an Austin-based company s ...

;

ITSN1 Intersectin-1 is a protein that, in humans, is encoded by the ''ITSN1'' gene. Function The protein encoded by this gene is a cytoplasmic membrane-associated protein that indirectly coordinates endocytic membrane traffic with the actin assembly ...

;

ITSN2 Intersectin-2 is a protein that in humans is encoded by the ''ITSN2'' gene. This gene encodes a cytoplasmic protein which contains SH3 domains. This protein is a member of a family of proteins involved in clathrin-mediated endocytosis. Intersecti ...

; KCNIP1;

KCNIP2 Kv channel-interacting protein 2 also known as KChIP2 is a protein that in humans is encoded by the ''KCNIP2'' gene. Function This gene encodes a member of the family of voltage-gated potassium ( Kv) channel-interacting proteins (KCNIPs, also ...

; KCNIP3;

KCNIP4 Kv channel-interacting protein 4 is a protein that in humans is encoded by the ''KCNIP4'' gene. This gene encodes a member of the family of voltage-gated potassium (Kv) channel-interacting proteins (KCNIPs), which belong to the recoverin branch o ...

; KIAA1799 *

LCP1 Plastin-2 is a protein that in humans is encoded by the ''LCP1'' gene. Function Plastins are a family of actin-binding proteins that are conserved throughout eukaryote evolution and expressed in most tissues of higher eukaryotes. In humans, t ...

MACF1 Microtubule-actin cross-linking factor 1, isoforms 1/2/3/5 is a protein that in humans is encoded by the ''MACF1'' gene. MACF1 encodes a large protein containing numerous spectrin and leucine-rich repeat (LRR) domains. MACF1 is a member of a fami ...

; MRLC2; MRLC3; MST133;

MYL1 Myosin light chain 3, skeletal muscle isoform is a protein that in humans is encoded by the ''MYL1'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ...

;

MYL2 Myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC-2) also known as the regulatory light chain of myosin (RLC) is a protein that in humans is encoded by the ''MYL2'' gene. This cardiac ventricular RLC isoform is distinct from ...

; MYL5;

MYL6B Myosin light chain 6B is a protein that in humans is encoded by the ''MYL6B'' gene. Myosin is a hexameric ATPase cellular motor protein. It is composed of two heavy chains, two nonphosphorylatable alkali light chains, and two phosphorylatable r ...

;

MYL7 Atrial Light Chain-2 (ALC-2) also known as Myosin regulatory light chain 2, atrial isoform (MLC2a) is a protein that in humans is encoded by the ''MYL7'' gene. ALC-2 expression is restricted to cardiac muscle atria in healthy individuals, where it ...

; MYL9; MYLC2PL; MYLPF * NCALD; NIN;

NKD1 Naked cuticle 1 (NKD1) is a human gene that encodes the protein Nkd1, a member of the Naked cuticle (Nkd) family of proteins that regulate the Wnt signaling pathway. Insects typically have a single Nkd gene, whereas there are two Nkd genes, Nkd1 an ...

;

NKD2 Naked cuticle 2 (NKD2) is a human gene that encodes the protein Nkd2, one of the Naked cuticle (Nkd) family of proteins that regulate the Wnt signaling pathway. Both Nkd1 and Nkd2 proteins can bind to Dishevelled proteins (DVL1, DVL2, DVL3), bu ...

; NLP; NOX5; NUCB1;

NUCB2 Nucleobindin-2 is a protein that when found in humans is encoded by the ''NUCB2'' gene. Nucleobindin-2 is a calcium-binding EF-hand protein. upplied by OMIMref name="entrez" /> NUCB2 is protein precursor of nesfatin-1 In the study of the evolut ...

* OCM *

PDCD6 Programmed cell death protein 6 is a protein that in humans is encoded by the ''PDCD6'' gene. This gene encodes a calcium-binding protein belonging to the penta-EF-hand protein family. Calcium binding is important for homodimerization and for con ...

;

PEF1 Peflin is a protein that in humans is encoded by the ''PEF1'' gene. PEF1 is a Ca(2+)-binding protein that belongs to the penta-EF hand (PEF) protein family, which includes the calpain small subunit (CAPNS1; MIM 114170), sorcin (SRI; MIM 182520), ...

;

PKD2 Polycystin-2 is a protein that in humans is encoded by the ''PKD2'' gene. This gene encodes a member of the polycystin protein family, called TRPP2, previously known as polycystin-2, PC2 or APKD2. TRPP2 contains multiple transmembrane domains, a ...

;

PLCD1 1-Phosphatidylinositol-4,5-bisphosphate phosphodiesterase delta-1 is an enzyme that in humans is encoded by the ''PLCD1'' gene. PLCd1 is essential to maintain homeostasis of the skin. See also Phospholipase C Phospholipase C (PLC) is a class of ...

;

PLCD4 1-Phosphatidylinositol-4,5-bisphosphate phosphodiesterase delta-4 is an enzyme that in humans is encoded by the ''PLCD4'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units o ...

; PLCH1;

PLCH2 PLCH may stand for: * Plch, a municipality in the Czech Republic * The Public Library of Cincinnati and Hamilton County Cincinnati and Hamilton County Public Library (CHPL) is a public library system in the United States. In addition t ...

;

PLS1 Fimbrin also known as is plastin 1 is a protein that in humans is encoded by the PLS1 gene. Fimbrin is an actin cross-linking protein important in the formation of filopodia. Structure Fimbrin belongs to the calponin homology (biology), homolog ...

;

PLS3 Plastin-3 is a highly conserved protein that in humans is encoded by the ''PLS3'' gene on the X chromosome. Function Plastins are a family of actin-binding proteins that are conserved throughout eukaryote evolution and expressed in most tissu ...

; PP1187;

PPEF1 Serine/threonine-protein phosphatase with EF-hands 1 is an enzyme that in humans is encoded by the ''PPEF1'' gene. Function This gene encodes a member of the serine/threonine protein phosphatase with EF-hand motif family. The protein contains ...

; PPEF2;

PPP3R1 Calcineurin subunit B type 1 also known as protein phosphatase 2B regulatory subunit 1 is a protein that in humans is encoded by the ''PPP3R1'' gene. Clinical significance The presence of a single nucleotide polymorphism rs1868402 in the ''PPP3 ...

;

PPP3R2 Calcineurin subunit B type 2 is a protein that in humans is encoded by the ''PPP3R2'' gene. Among its related pathways are MAPK/ERK pathway, MAPK signaling pathway and GPCR pathway. GO annotations related to this gene include calcium ion binding. ...

;

PRKCSH Glucosidase 2 subunit beta is an enzyme that in humans is encoded by the ''PRKCSH'' gene. This gene encodes the beta-subunit of glucosidase II, an N-linked glycan-processing enzyme in the endoplasmic reticulum (ER). This protein is an acidic pho ...

; PVALB *

RAB11FIP3 Rab11 family-interacting protein 3 is a protein that in humans is encoded by the ''RAB11FIP3'' gene. Proteins of the large Rab GTPase family (see RAB1A; MIM 179508) have regulatory roles in the formation, targeting, and fusion of intracellular tr ...

;

RASEF Ras and EF-hand domain-containing protein also known as Ras-related protein Rab-45 is a protein that in humans is encoded by the RASEF gene. The RASEF gene is located on chromosome 9 (9q21.32). Introduction RASEF belongs to the small GTPase ...

; RASGRP;

RASGRP1 RAS guanyl-releasing protein 1 is a protein that in humans is encoded by the ''RASGRP1'' gene. Function RAS guanyl nucleotide-releasing protein (RASGRP) is a member of a family of genes characterized by the presence of a Ras superfamily guanin ...

; RASGRP2;

RASGRP3 Ras guanyl-releasing protein 3 is a protein that in humans is encoded by the ''RASGRP3'' gene. Function Members of the RAS (see HRAS; MIM 190020) subfamily of GTPases function in signal transduction as GTP/GDP-regulated switches that cycle bet ...

;

RCN1 Reticulocalbin-1 is a protein that in humans is encoded by the ''RCN1'' gene. Reticulocalbin 1 is a calcium-binding protein located in the lumen of the ER. The protein contains six conserved regions with similarity to a high affinity Ca(+2)-bind ...

; RCN2; RCN3; RCV1; RCVRN;

REPS1 RalBP1-associated Eps domain-containing protein 1 is a protein that in humans is encoded by the ''REPS1'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." ...

; RHBDL3;

RHOT1 Mitochondrial Rho GTPase 1 (MIRO1) is an enzyme that in humans is encoded by the ''RHOT1'' gene on chromosome 17. As a Miro (protein), Miro protein isoform, the protein facilitates mitochondrial transport by attaching the mitochondria to the motor ...

;

RHOT2 Mitochondrial Rho GTPase 2 is an enzyme that in humans is encoded by the ''RHOT2'' gene. As a Miro (protein), Miro protein isoform, the protein facilitates mitochondrial transport by attaching the mitochondria to the motor/adaptor complex. Through ...

; RPTN;

RYR2 Ryanodine receptor 2 (RYR2) is one of a class of ryanodine receptors and a protein found primarily in cardiac muscle. In humans, it is encoded by the ''RYR2'' gene. In the process of cardiac calcium-induced calcium release, RYR2 is the major medi ...

;

RYR3 Ryanodine receptor 3 is one of a class of ryanodine receptors and a protein that in humans is encoded by the ''RYR3'' gene. The protein encoded by this gene is both a calcium channel and a receptor for the plant alkaloid ryanodine. RYR3 and RY ...

S100A1 Protein S100-A1, also known as S100 calcium-binding protein A1 is a protein which in humans is encoded by the ''S100A1'' gene. S100A1 is highly expressed in cardiac and skeletal muscle, and localizes to Z-discs and sarcoplasmic reticulum. S100A1 ...

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S100A11 S100 calcium-binding protein A11 (S100A11) is a protein that in humans is encoded by the ''S100A11'' gene. Function The protein encoded by this gene is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100A ...

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S100A12 S100 calcium-binding protein A12 (S100A12) is a protein that in humans is encoded by the ''S100A12'' gene. Human S100A12, also known as calgranulin C, was first described in 1995. The protein encoded by this gene is a member of the S100 family of ...

; S100A6;

S100A8 S100 calcium-binding protein A8 (S100A8) is a protein that in humans is encoded by the ''S100A8'' gene. It is also known as calgranulin A. The proteins S100A8 and S100A9 form a heterodimer called calprotectin Calprotectin is a multiprotein co ...

;

S100A9 S100 calcium-binding protein A9 (S100A9) also known as migration inhibitory factor-related protein 14 (MRP14) or calgranulin B is a protein that in humans is encoded by the ''S100A9'' gene. The proteins S100A8 and S100A9 form a heterodimer calle ...

;

S100B S100 calcium-binding protein B (S100B) is a protein of the S-100 protein family. S100 proteins are localized in the cytoplasm and nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cyc ...

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S100G S100 calcium-binding protein G (S100G) is a protein that in humans is encoded by the ''S100G'' gene. This gene encodes calbindin Calbindins are three different calcium-binding proteins: calbindin, calretinin and S100G. They were origina ...

; S100Z; SCAMC-2;

SCGN Secretagogin is a protein that in humans is encoded by the ''SCGN'' gene. Function The encoded protein is a secreted calcium-binding protein which is found in the cytoplasm. It is related to calbindin D-28K and calretinin. This protein is tho ...

;

SCN5A Sodium channel protein type 5 subunit alpha, also known as NaV1.5 is an integral membrane protein and tetrodotoxin-resistant voltage-gated sodium channel subunit. NaV1.5 is found primarily in cardiac muscle, where it mediates the fast influx of N ...

;

SDF4 45 kDa calcium-binding protein is a protein that in humans is encoded by the ''SDF4'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generati ...

; SLC25A12; SLC25A13; SLC25A23; SLC25A24; SLC25A25; SPATA21;

SPTA1 Spectrin alpha chain, erythrocyte is a protein that in humans is encoded by the ''SPTA1'' gene. Spectrin is an actin crosslinking and molecular scaffold protein that links the plasma membrane to the actin cytoskeleton, and functions in the deter ...

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SPTAN1 Alpha II-spectrin, also known as Spectrin alpha chain, brain is a protein that in humans is encoded by the ''SPTAN1'' gene. Alpha II-spectrin is expressed in a variety of tissues, and is highly expressed in cardiac muscle at Z-disc structures, co ...

;

SRI Shri (; , ) is a Sanskrit term denoting resplendence, wealth and prosperity, primarily used as an honorific. The word is widely used in South and Southeast Asian languages such as Marathi, Malay (including Indonesian and Malaysian), Javanes ...

* TBC1D9; TBC1D9B;

TCHH Trichohyalin is a protein that in mammals is encoded by the ''TCHH'' gene. Discovery In 1903 the name ''trichohyalin'' was assigned to the granules of the inner root sheath (IRS) of hair follicles discovered by Hans Vörner. In 1986 the name was ...

; TESC;

TNNC1 Troponin C, also known as TN-C or TnC, is a protein that resides in the troponin complex on actin thin filaments of striated muscle (cardiac, fast-twitch skeletal, or slow-twitch skeletal) and is responsible for binding calcium to activate muscle ...

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TNNC2 Troponin C, skeletal muscle is a protein that in humans is encoded by the ''TNNC2'' gene. Troponin (Tn), is a key protein complex in the regulation of striated muscle contraction, composed of three subunits. The TnI subunit inhibits actomyosin ...

* USP32 * VSNL1 * ZZEF1

References

External links

* * * * * * * {{Protein secondary structure