Accessory gene regulator B (IPR006741)

Short name: AgrB

Family relationships



This entry represents the accessory gene regulator protein B (AgrB) family. Proteins in this family include AgrB from Staphylococcus aureus and FsrB from Enterococcus faecalis.

The accessory gene regulator (agr) of Staphylococcus aureus is the central regulatory system that controls the gene expression for a large set of virulence factors. The arg locus consists of two transcripts: RNAII and RNAIII. RNAII encodes four genes (agrA, B, C, and D) whose gene products assemble a quorum sensing system. At low cell density, the agr genes are continuously expressed at basal levels. A signal molecule, autoinducing peptide (AIP), produced and secreted by the bacteria, accumulates outside of the cells. When the cell density increases and the AIP concentration reaches a threshold, it activates the agr response, i.e. activation of secreted protein gene expression and subsequent repression of cell wall-associated protein genes. AgrB and AgrD are essential for the production of the autoinducing peptide which functions as a signal for quorum sensing. AgrB is a transmembrane protein [PMID: 11195102] involved in the proteolytic processing of AgrD, and may have both proteolytic and transporter activities, facilitating the export of the processed AgrD peptide [PMID: 12122003].

FsrB may be involved in the proteolytic processing of a quorum sensing system signal molecule precursor required for the regulation of the virulence genes for gelatinase (gelE) and a serine protease (sprE) [PMID: 10768947].

GO terms

Biological Process

GO:0009405 pathogenesis
GO:0009372 quorum sensing

Molecular Function

GO:0008233 peptidase activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

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