Active Site

Peptidase C14, ICE, catalytic subunit p20, active site (IPR016129)

Short name: Pept_C14_ICE_p20_AS


These signature contain the active site histidine and cysteine residues that are found in the p20 subunit of caspases. Caspases are composed of an N-terminal pro-domain that is cleaved during activation, and C-terminal catalytic and interaction domains [PMID: 15226512]. All caspases contain two essential caspase catalytic domains: the p20 subunit (20 kDa) and the p10 subunit (10 kDa) (IPR002138), which are derived from the p45 (45 kDa) precursor (IPR002398). Caspases are tightly regulated proteins that require zymogen activation to become active, and once active can be regulated by caspase inhibitors. Activated caspases are cysteine proteases (MEROPS clan CD, family C14) that use the sulphydryl group of a cysteine side chain for catalysing peptide bond cleavage at aspartyl residues in their substrates. The key catalytic residues, a cysteine and a histidine, are on the p20 subunit.

Caspases are mainly involved in mediating cell death (apoptosis), either as initiators that trigger the cell death process, or as effectors of the process itself [PMID: 10578171, PMID: 15077141]. At the end of the cascade, caspases act on a variety of signal transduction proteins, cytoskeletal and nuclear proteins, chromatin-modifying proteins, DNA repair proteins and endonucleases that destroy the cell by disintegrating its contents, including its DNA. Caspases can have roles other than in apoptosis, such as caspase-1 (interleukin-1 beta convertase) (EC:, which is involved in the inflammatory process. The activation of apoptosis can sometimes lead to caspase-1 activation, providing a link between apoptosis and inflammation, such as during the targeting of infected cells. Caspases may also be involved in cell differentiation [PMID: 15066636].

GO terms

Biological Process

GO:0006508 proteolysis

Molecular Function

GO:0004197 cysteine-type endopeptidase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns
PROSITE patterns