Domain

Proteasome alpha-subunit, N-terminal domain (IPR000426)

Short name: Proteasome_asu_N

Domain relationships

None.

Description

The proteasome (or macropain) (EC:3.4.25.1) [PMID: 7682410, PMID: 2643381, PMID: 1317508, PMID: 7697118, PMID: 8882582] is a multicatalytic proteinase complex in eukaryotes and archaea, and in some bacteria, that is involved in an ATP/ubiquitin-dependent non-lysosomal proteolytic pathway. In eukaryotes the 20S proteasome is composed of 28 distinct subunits which form a highly ordered ring-shaped structure (20S ring) of about 700 kDa. Proteasome subunits can be classified on the basis of sequence similarities into two groups, alpha (A) and beta (B). The proteasome consists of four stacked rings composed of alpha/beta/beta/alpha subunits. There are seven different alpha subunits and seven different beta subunits [PMID: 9087403]. Three of the seven beta subunits are peptidases, each with a different specificity. Subunit beta1c (MEROPS identifier T01.010) has a preference for cleaving glutaminyl bonds ("peptidyl-glutamyl-like" or "caspase-like"), subunit beta2c (MEROPS identifier T01.011) has a preference for cleaving arginyl and lysyl bonds ("trypsin-like"), and subunit beta5c (MEROPS identifier T01.012) cleaves after hydrophobic amino acids ("chymotrypsin-like") [PMID: 2535672]. The proteasome subunits are related to N-terminal nucleophile hydrolases, and the catalytic subunits have an N-terminal threonine nucleophile.

Subunits that belong to the A group are proteins of from 210 to 290 amino acids. They are classified as non-peptidase homologues in MEROPS peptidase family T1 (clan PB(T)).

This entry represents an N-terminal domain conserved in the A subunits of the proteasome complex.

GO terms

Biological Process

GO:0006511 ubiquitin-dependent protein catabolic process

Molecular Function

GO:0004175 endopeptidase activity

Cellular Component

GO:0019773 proteasome core complex, alpha-subunit complex

Contributing signatures

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