Interaction of Bacillus subtilis CsaA with SecA and precursor proteins.
CsaA from the Gram-positive bacterium Bacillus subtilis has been identified previously as a suppressor of the growth and protein-export defect of Escherichia coli secA(Ts) mutants. CsaA has chaperone-like activities in vivo and in vitro. To examine the role of CsaA in protein export in B. subtilis, expression of the csaA gene was repressed. While export of most proteins remained unaffected, export of at least two proteins was significantly reduced upon CsaA depletion. CsaA co-immunoprecipitates and co-purifies with the SecA proteins of E. coli and B. subtilis, and binds the B. subtilis preprotein prePhoB. Purified CsaA stimulates the translocation of prePhoB into E. coli membrane vesicles bearing the B. subtilis translocase, whereas it interferes with the SecB-mediated translocation of proOmpA into membrane vesicles of E. coli. The specific interaction with the SecA translocation ATPase and preproteins suggests that CsaA acts as a chaperone that promotes the export of a subset of preproteins in B. subtilis.
Müller
J P
JP
Institute for Molecular Biology, Jena University, Winzerlaer Strasse 10, D-07745 Jena, Germany. jmueller@imb-jena.de
Ozegowski
J
J
Vettermann
S
S
Swaving
J
J
Van Wely
K H
KH
Driessen
A J
AJ
D000251:Adenosine Triphosphatases / Q000302:isolation & purification / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D005838:Genotype; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; D010641:Phenotype; D010957:Plasmids; D011485:Protein Binding; D011498:Protein Precursors / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; D011498:Protein Precursors; D011994:Recombinant Proteins; D000069816:SEC Translocation Channels; C061278:PhoB protein, Bacteria; C077891:CsaA protein, Bacillus subtilis; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins