Abstract
Proteins in the YidC/Oxa1/Alb3 family have essential functions in membrane protein insertion and folding. Bacillus subtilis encodes two YidC homologs, one that is constitutively expressed (spoIIIJ/yidC1) and a second (yqjG/yidC2) that is induced in spoIIIJ mutants. Regulated induction of yidC2 allows B. subtilis to maintain capacity of the membrane protein insertion pathway. We here show that a gene located upstream of yidC2 (mifM/yqzJ) serves as a sensor of SpoIIIJ activity that regulates yidC2 translation. Decreased SpoIIIJ levels or deletion of the MifM transmembrane domain arrests mifM translation and unfolds an mRNA hairpin that otherwise blocks initiation of yidC2 translation. This regulated translational arrest and yidC2 induction require a specific interaction between the MifM C-terminus and the ribosomal polypeptide exit tunnel. MifM therefore acts as a ribosome-nascent chain complex rather than as a fully synthesized protein. B. subtilis MifM and the previously described secretion monitor SecM in Escherichia coli thereby provide examples of the parallel evolution of two regulatory nascent chains that monitor different protein export pathways by a shared molecular mechanism.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
