Caspase 2 also known as CASP2 is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

that, in humans, is encoded by the ''CASP2''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. ''CASP2''

orthologs Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a spe ...

have been identified in nearly all mammals for which complete genome data are available. Unique orthologs are also present in

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia al ...

s, lissamphibians, and

teleost Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Tel ...

Function

Sequential activation of

caspase Caspases (cysteine-aspartic proteases, cysteine aspartases or cysteine-dependent aspartate-directed proteases) are a family of protease enzymes playing essential roles in programmed cell death. They are named caspases due to their specific cyst ...

s plays a central role in the execution-phase of cell apoptosis. Caspases exist as inactive proenzymes that undergo proteolytic processing at conserved aspartic residues to produce two subunits, large and small, that dimerize to form the active enzyme. The proteolytic cleavage of this protein is induced by a variety of apoptotic stimuli. Caspase 2 proteolytically cleaves other proteins. It belongs to a family of

cysteine protease Cysteine proteases, also known as thiol proteases, are hydrolase enzymes that degrade proteins. These proteases share a common catalytic mechanism that involves a nucleophilic cysteine thiol in a catalytic triad or dyad. Discovered by Gopal ...

s called

s that cleave proteins only at an

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 ...

following an

aspartic acid 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 pr ...

residue. Within this family, caspase 2 is part of the Ich-1 subfamily. It is one of the most conserved caspases in different

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of animal. Caspase 2 has a similar amino acid sequence to initiator caspases, including

caspase 1 Caspase-1/Interleukin-1 converting enzyme (ICE) is an evolutionarily conserved enzyme that proteolytically cleaves other proteins, such as the precursors of the inflammatory cytokines interleukin 1β and interleukin 18 as well as the pyroptos ...

caspase 4 Caspase 4 is an enzyme that proteolytically cleaves other proteins at an aspartic acid residue (LEVD-), and belongs to a family of cysteine proteases called caspases. The function of caspase 4 is not fully known, but it is believed to be an in ...

, caspase 5, and

caspase 9 Caspase-9 is an enzyme that in humans is encoded by the CASP9 gene. It is an initiator caspase, critical to the apoptotic pathway found in many tissues. Caspase-9 homologs have been identified in all mammals for which they are known to exist, such ...

. It is produced as a

zymogen In biochemistry, a zymogen (), also called a proenzyme (), is an inactive precursor of an enzyme. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the acti ...

, which contains a long pro-domain that is similar to that of caspase 9 and contains a protein interaction domain known as a

CARD domain Caspase recruitment domains, or caspase activation and recruitment domains (CARDs), are interaction motifs found in a wide array of proteins, typically those involved in processes relating to inflammation and apoptosis. These domains mediate t ...

. Pro-caspase-2 contains two subunits, p19 and p12. It has been shown to associate with several proteins involved in apoptosis using its CARD domain, including RIP-associated Ich-1/Ced-3-homologue protein with a death domain ( RAIDD), apoptosis repressor with caspase recruitment domain (ARC), and death effector filament-forming Ced-4-like apoptosis protein ( DEFCAP). Together with RAIDD and p53-induced protein with a death domain ( IDD( LRDD), caspase 2 has been shown to form the so-called PIDDosome, which may serve as an activation platform for the protease, although it may also be activated in the absence of PIDD. Overall, caspase 2 appears to be a very versatile caspase with multiple functions beyond cell death induction.

Interactions

Caspase 2 has been shown to interact with: *

BH3 interacting domain death agonist The BH3 interacting-domain death agonist, or BID, gene is a pro-apoptotic member of the Bcl-2 protein family. Bcl-2 family members share one or more of the four characteristic domains of homology entitled the Bcl-2 homology (BH) domains (named ...

, *

CRADD Death domain-containing protein CRADD is a protein that in humans is encoded by the ''CRADD'' gene. Function The protein encoded by this gene is a death domain (CARD/DD)-containing protein and has been shown to induce cell apoptosis. Through ...

, and *

Caspase 8 Caspase-8 is a caspase protein, encoded by the ''CASP8'' gene. It most likely acts upon caspase-3. ''CASP8'' orthologs have been identified in numerous mammals for which complete genome data are available. These unique orthologs are also prese ...

References

External links

* The

MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibi ...

online database for peptidases and their inhibitors
C14.006
* {{Portal bar, Biology, border=no EC 3.4.22 Caspases

Function

Interactions

See also

References

External links