Effects of two sec genes on protein assembly into the plasma membrane of Escherichia coli.
We have examined the effects of thermosensitive mutations in secA and secY (prlA) genes on the export of proteins to the three layers of the Escherichia coli cell surface. After several hours at the nonpermissive temperature, the export of two major outer membrane proteins, lipoprotein and OmpA, is delayed, then essentially blocked, in either a secA or secY strain. These mutations also have a strong effect on the export of several proteins, such as maltose binding protein, to the periplasm, though the export of many periplasmic proteins is not affected. secA and secY block the assembly of leader peptidase, which is made without a leader sequence, into the inner membrane. However, the membrane assembly of M13 coat protein (an inner membrane protein made with an amino-terminal leader sequence) is not affected. Thus, the requirement for sec function for export does not correlate with the presence or absence of leader peptide or with a particular subcellular compartment, but rather is specific to each particular protein.
D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport; D002213:Capsid / Q000378:metabolism; D036022:Capsid Proteins; D002352:Carrier Proteins / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006358:Hot Temperature; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D033902:Periplasmic Binding Proteins; D011498:Protein Precursors / Q000378:metabolism; D012697:Serine Endopeptidases
D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D036022:Capsid Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011498:Protein Precursors; C025668:coat protein, Bacteriophage M13; C461599:maltose transport system, E coli; D010450:Endopeptidases; D012697:Serine Endopeptidases; C026515:type I signal peptidase