Staphylococcal AgrD (IPR009229)

Short name: AgrD

Overlapping homologous superfamilies


Family relationships



Members of this family of short peptides are precursors to thiolactone (unless Cys is replaced by Ser) cyclic autoinducer peptides, used in quorum-sensing systems in Gram-positive bacteria. The best characterised is the AgrD precursor, processed by the AgrB protein. Nearby proteins regularly encountered include a histidine kinase and a response regulator.

The agr locus was initially described in Staphylococcus aureus as an element controlling the production of exoproteins implicated in virulence. Its pattern of action has been shown to be complex, upregulating certain extracellular toxins and enzymes expressed post-exponentially and repressing some exponential-phase surface components. AgrD encodes the precursor of the autoinducing peptide (AIP).The AIP derived from AgrD by the action of AgrB interacts with AgrC in the membrane to activate AgrA, which upregulates transcription both from promoter P2, amplifying the response, and from P3, initiating the production of a novel effector: RNAIII. In S. aureus, delta-hemolysin is the only translation product of RNA III and is not involved in the regulatory functions of the transcript, which is therefore the primary agent for modulating the expression of other operons controlled by agr [PMID: 11807079].

Contributing signatures

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