Protein secretion by hybrid bacterial ABC-transporters: specific functions of the membrane ATPase and the membrane fusion protein.
The Erwinia chrysanthemi metalloprotease C and the Serratia marcescens haem acquisition protein HasA are both secreted from Gram-negative bacteria by a signal peptide-independent pathway which requires a C-terminal secretion signal and a specific ABC-transporter made up of three proteins: a membrane ATPase (the ABC-protein), a second inner membrane component belonging to the membrane fusion protein family and an outer membrane polypeptide. HasA and protease C transporters are homologous although the secreted polypeptides share no sequence homology. Whereas protease C can use both translocators, HasA is secreted only by its specific transporter. Functional analysis of protease C and HasA secretion through hybrid transporters obtained by combining components from each system demonstrates that the ABC-protein is responsible for the substrate specificity and that inhibition of protease C secretion in the presence of HasA results from a defective interaction between HasA and the ABC-protein. We also show that the outer membrane protein, TolC, can combine with the membrane fusion protein HasE in the presence of either ABC-protein to form a functional transporter but not with the membrane fusion protein, PrtE. This indicates a specific interaction between the outer membrane component and the membrane fusion protein.
Binet
R
R
Unité de Physiologie Cellulaire, Institut Pasteur Centre National de la Recherche Scientifique, Paris, France.
Wandersman
C
C
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001667:Binding, Competitive; D001692:Biological Transport; D002352:Carrier Proteins; D017364:Collagenases / Q000378:metabolism*; D016974:Dickeya chrysanthemi / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012706:Serratia marcescens / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C093956:HasA protein, Serratia marcescens; C093958:HasE protein, Serratia marcescens; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C093955:PrtF protein, bacteria; D011993:Recombinant Fusion Proteins; C073126:tolC protein, E coli; D017364:Collagenases; C074887:prtC protein, bacteria; D000251:Adenosine Triphosphatases; C093959:HasD protein, Serratia marcescens