Regulation of Escherichia coli secA by cellular protein secretion proficiency requires an intact gene X signal sequence and an active translocon.
secA is translationally regulated by the protein secretion proficiency state of the Escherichia coli cell. This regulation was explored by making signal sequence mutations in the gene upstream of secA, gene X, which promotes secA translational coupling. Gene X signal sequence mutants were constitutive for secA expression, while prlA alleles partially restored secA regulation. These results show that interaction of the pre-gene X protein with the translocon is required for proper secA regulation. Furthermore, gene X signal sequence mutations disrupted secA regulation only in the cis configuration. We propose that nascent pre-gene X protein interacts with the translocon during its secretion to constitute the secretion sensor.
Oliver
D
D
Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, Connecticut 06459, USA doliver@wesleyan.edu
Norman
J
J
Sarker
S
S
D000251:Adenosine Triphosphatases / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D026901:Membrane Transport Proteins; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics*; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D021382:Protein Sorting Signals; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins