AgrB

Accessory gene regulator B
AgrB
SMART accession number:SM00793
Description: 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 (PUBMED:11195102). AgrB is involved in the proteolytic processing of AgrD and may have both proteolytic enzyme activity and a transporter facilitating the export of the processed AgrD peptide (PUBMED:12122003).
Interpro abstract (IPR006741):

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 [(PUBMED:11195102)] involved in the proteolytic processing of AgrD, and may have both proteolytic and transporter activities, facilitating the export of the processed AgrD peptide [(PUBMED: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) [(PUBMED:10768947)].

GO process:pathogenesis (GO:0009405), quorum sensing (GO:0009372)
GO component:integral component of membrane (GO:0016021)
GO function:peptidase activity (GO:0008233)
Family alignment:
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There are 753 AgrB domains in 753 proteins in SMART's nrdb database.

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