Phosphatase RapC/F inhibitor, PhrC/F (IPR025899)

Short name: PhrC_PhrF

Overlapping homologous superfamilies


Family relationships


In the field of cell-cell communication, an emerging class of extracellular signalling peptides that function intracellularly has been identified in Gram-positive bacteria. One illustrative member of this group is the Phr family of extracellular signaling peptides of Bacillus subtilis. The Phr signalling peptides are secreted by the bacterium, and then, despite the presence of intracellular peptidases, they are actively transported into the cell where they interact with intracellular receptors to regulate gene expression. The intracellular receptors are members of a family of aspartyl-phosphate phosphatases, the Rap phosphatases. These phosphatases cause the dephosphorylation of response regulator proteins, ubiquitous regulatory proteins in bacteria. Immediately downstream of the genes for the Rap phosphatases are the genes for the Phr peptides, forming rap phr signalling cassettes. There are at least seven rap phr signalling cassettes in B. subtilis, and the genome sequence of other Gram-positive, endospore-forming bacteria suggests that similar cassettes may also function in these bacteria. In B. subtilis, the rap phr cassettes regulate sporulation, genetic competence, and genes comprising the quorum response (i.e. the response to high cell density) [PMID: 12456319].

The Phr genes are processed, probably by a single processing event that cleaves off the C-terminal pentapeptide. These pentapeptides inhibit specific phosphatases that are regulators of response regulator transcription factors. The PhrA (ARNQT) and PhrE (SRNVT) peptides inhibit the RapA and RapE phosphatases, respectively, whose activity is directed toward the Spo0F approximately P intermediate response regulator of the sporulation phosphorelay; while the PhrC (ERGMT) peptide inhibits the RapC protein acting on the ComA response regulator for competence with regard to DNA transformation [PMID: 8769645, PMID: 12897006].

PhrF stimulate ComA-dependent gene expression to different levels and are both required for full expression of genes activated by ComA, which activates the expression of genes involved in competence development and the production of several secreted products [PMID: 16816200].

Contributing signatures

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