Prc (PA3257) is a 698-residue periplasmic tail-specific protease of Pseudomonas aeruginosa PAO1, a carboxyl-terminal processing serine protease of the peptidase S41A family with a Sec signal peptide, a PDZ domain and an S41 catalytic domain. Prc acts as a site-1 protease in regulated proteolysis of anti-sigma factors. It degrades mutant forms of the anti-sigma factor MucA, releasing the AlgU sigma factor and promoting mucoidy in cystic fibrosis isolates, and in cell-surface signalling systems it removes the periplasmic anti-sigma domain so that RseP can then cleave the transmembrane segment and release the active extracytoplasmic function sigma factor.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004175 endopeptidase activity | IBA GO_REF:0000033 | MODIFY | Summary: IBA endopeptidase activity from PTN000786001 (seeds B. subtilis CtpB and E. coli Prc). Reason: Correct but general. Prc is an S41A serine protease, so the specific term is GO:0004252 serine-type endopeptidase activity, an is_a descendant of endopeptidase activity. Propagation Review Root cause: NO FAILURE CORE Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN000786001 · PTN000786001 SUPPORTS TRANSFER CTP family node; the generic endopeptidase term transfers correctly. The gene-level term is the serine-type endopeptidase descendant. UniProtKB:P23865 · E. coli Prc (Tsp) SUPPORTS TRANSFER Characterised orthologous tail-specific protease. UniProtKB:O35002 · B. subtilis CtpB SUPPORTS TRANSFER Characterised CTP family member. Proposed replacements: serine-type endopeptidase activity Supporting Evidence: file:PSEAE/prc/prc-uniprot.txt Pfam; PF03572; Peptidase_S41; 1. file:PSEAE/prc/prc-uniprot.txt NCBIfam; TIGR00225; prc; 1. |
| GO:0006508 proteolysis | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro2GO proteolysis from the S41A peptidase signatures. Reason: Correct process for a tail-specific protease that degrades anti-sigma factors. Supporting Evidence: PMID:24082078 Prc degrades mutant forms of the anti-sigma factor MucA to promote mucoidy in some cystic fibrosis lung isolates. |
| GO:0007165 signal transduction | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN001279639, seeded by Prc itself, B. subtilis CtpB and PA5134 (CtpA). The self-seed reflects Prc's own experimental row; the PA5134 seed is wrong (see the PA5134 review). Reason: True for Prc on its own evidence: it performs the site-1 cleavage of anti-sigma factors in cell-surface signalling. The node-level placement concern is recorded once, on PA5134. Supporting Evidence: PMID:24373018 Prc, which removes the periplasmic anti-sigma domain, and RseP, which subsequently removes the transmembrane domain and thereby generates the ECF active transcriptional form. |
| GO:0007165 signal transduction | IMP PMID:24373018 The Prc and RseP proteases control bacterial cell-surface si... | ACCEPT | Summary: PseudoCAP row and a seed of the PTN001279639 IBD. Prc and RseP sequentially process the anti-sigma domain to release the active ECF sigma factor in cell-surface signalling. Reason: Sound seed. Prc does a step of the signalling pathway (removing the periplasmic anti-sigma domain), not merely a mutant phenotype. The Iut experiments are in P. putida; the abstract does not say which organism the classical-CSS experiments used, and the curator read the paper. Supporting Evidence: PMID:24373018 We furthermore demonstrate the role of these proteases in the regulation of classical CSS systems |
| GO:0008236 serine-type peptidase activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO serine-type peptidase from the S41A signatures. Reason: Correct but general; Prc is an endopeptidase that cleaves within anti-sigma factors, so the specific term is GO:0004252 serine-type endopeptidase activity (is_a serine-type peptidase). Proposed replacements: serine-type endopeptidase activity Supporting Evidence: file:PSEAE/prc/prc-uniprot.txt Pfam; PF03572; Peptidase_S41; 1. |
| GO:0030288 outer membrane-bounded periplasmic space | IBA GO_REF:0000033 | ACCEPT | Summary: IBA periplasmic location from PTN001279639 (seed E. coli Prc). Reason: Consistent with the Sec signal peptide and with Prc cleaving the periplasmic domain of anti-sigma factors. Supporting Evidence: file:PSEAE/prc/prc-uniprot.txt SIGNAL 1..23 PMID:24373018 Prc, which removes the periplasmic anti-sigma domain |
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Download this section (compressed HTML)Q: Which features of an anti-sigma factor's periplasmic domain does Prc recognise, and why does it cleave mutant but not wild-type MucA?
Experiment: In vitro cleavage of purified periplasmic anti-sigma domains (wild-type and truncated MucA, CSS anti-sigma factors) by purified Prc, mapping cleavage sites by mass spectrometry.
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