Identification of Bacillus subtilis SipW as a Bifunctional Signal Peptidase That Controls Surface-Adhered Biofilm Formation

Rebecca Terra, Nicola R. Stanley-Wall, Guoqiang Cao, Beth A. Lazazzera

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    45 Citations (Scopus)


    Biofilms of microbial cells encased in an exopolymeric matrix can form on solid surfaces, but how bacteria sense a solid surface and upregulate biofilm genes is largely unknown. We investigated the role of the Bacillus subtilis signal peptidase, SipW, which has a unique role in forming biofilms on a solid surface and is not required at an air-liquid interface. Surprisingly, we found that the signal peptidase activity of SipW was not required for solid-surface biofilms. Furthermore, a SipW mutant protein was constructed that lacks the ability to form a solid-surface biofilm but still retains signal peptidase activity. Through genetic and gene expression tests, the non-signal peptidase role of SipW was found to activate biofilm matrix genes specifically when cells were on a solid surface. These data provide the first evidence that a signal peptidase is bifunctional and that SipW has a regulatory role in addition to its role as a signal peptidase.

    Original languageEnglish
    Pages (from-to)2781-2790
    Number of pages10
    JournalJournal of Bacteriology
    Issue number11
    Publication statusPublished - Jun 2012

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