title: Bacillus subtilis SpoIIIJ and YqjG function in membrane protein biogenesis.
abstract: In all domains of life Oxa1p-like proteins are involved in membrane protein biogenesis. Bacillus subtilis, a model organism for gram-positive bacteria, contains two Oxa1p homologs: SpoIIIJ and YqjG. These molecules appear to be mutually exchangeable, although SpoIIIJ is specifically required for spore formation. SpoIIIJ and YqjG have been implicated in a posttranslocational stage of protein secretion. Here we show that the expression of either spoIIIJ or yqjG functionally compensates for the defects in membrane insertion due to YidC depletion in Escherichia coli. Both SpoIIIJ and YqjG complement the function of YidC in SecYEG-dependent and -independent membrane insertion of subunits of the cytochrome o oxidase and F(1)F(o) ATP synthase complexes. Furthermore, SpoIIIJ and YqjG facilitate membrane insertion of F(1)F(o) ATP synthase subunit c from both E. coli and B. subtilis into inner membrane vesicles of E. coli. When isolated from B. subtilis cells, SpoIIIJ and YqjG were found to be associated with the entire F(1)F(o) ATP synthase complex, suggesting that they have a role late in the membrane assembly process. These data demonstrate that the Bacillus Oxa1p homologs have a role in membrane protein biogenesis rather than in protein secretion.
authors.affiliation: Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Kluyver Centre for the Genomics of Industrial Fermentations and the Zernike Institute of Advanced Materials, University of Groningen, 9751 NN Haren, The Netherlands.
authors.forename: Manfred J
authors.initials: MJ
authors.lastname: Saller
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Fusetti
authors.forename: Arnold J M
authors.initials: AJ
authors.lastname: Driessen
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C412443:YIDC protein, E coli; C030069:spore-specific proteins, Bacillus; C038862:cytochrome o oxidase; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases