Reconstitution of the S. aureus agr quorum sensing pathway reveals a direct role for the integral membrane protease MroQ in pheromone biosynthesis

Aishan Zhao, Steven P. Bodine, Qian Xie, Boyuan Wang, Geeta Ram, Richard P. Novick, Tom W. Muir

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


In Staphylococcus aureus, virulence is under the control of a quorum sensing (QS) circuit encoded in the accessory gene regulator (agr) genomic locus. Key to this pathogenic behavior is the production and signaling activity of a secreted pheromone, the autoinducing peptide (AIP), generated following the ribosomal synthesis and posttranslational modification of a precursor polypeptide, AgrD, through two discrete cleavage steps. The integral membrane protease AgrB is known to catalyze the first processing event, generating the AIP biosynthetic intermediate, AgrD (1–32) thiolactone. However, the identity of the second protease in this biosynthetic pathway, which removes an N-terminal leader sequence, has remained ambiguous. Here, we show that membrane protease regulator of agr QS (MroQ), an integral membrane protease recently implicated in the agr response, is directly involved in AIP production. Genetic complementation and biochemical experiments reveal that MroQ proteolytic activity is required for AIP biosynthesis in agr specificity group I and group II, but not group III. Notably, as part of this effort, the biosynthesis and AIP-sensing arms of the QS circuit were reconstituted together in vitro. Our experiments also reveal the molecular features guiding MroQ cleavage activity, a critical factor in defining agr specificity group identity. Collectively, our study adds to the molecular understanding of the agr response and Staphylococcus aureus virulence.

Original languageEnglish (US)
Article numbere2202661119
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number33
StatePublished - Aug 16 2022

All Science Journal Classification (ASJC) codes

  • General


  • RiPP biosynthesis
  • Staphylococcus aureus
  • bacterial pathogenesis
  • quorum sensing
  • synthetic biology


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