Role of CspC and CspE in regulation of expression of RpoS and UspA, the stress response proteins in Escherichia coli.
Nine homologous proteins, CspA to CspI, constitute the CspA family of Escherichia coli. Recent studies are aimed at elucidating the individual cellular functions of these proteins. Two members of this family, CspC and CspE, are constitutively produced at 37 degrees C. In the present study, these two proteins were evaluated for their cellular role(s). The expression of three stress proteins, OsmY, Dps, and UspA, is significantly affected by the overexpression and deletion of CspC and CspE. RpoS is a regulatory element for osmY and dps. Further analysis showed a larger amount and greater stability of the rpoS mRNA as well as a higher level of RpoS itself with the overexpression of CspC and CspE. This suggests that CspC and CspE upregulate the expression of OsmY and Dps by regulating the expression of RpoS itself. Indeed, this upregulation is lost in the Delta rpoS strain. Other RpoS-controlled proteins such as ProP and KatG, are also upregulated by the overexpression of CspC. The present study suggests that CspC and CspE are the important elements involved in the regulation of the expression of RpoS, a global stress response regulator, and UspA, a protein responding to numerous stresses. In the light of these observations, it seems plausible that CspC and CspE function as regulatory elements for the expression of stress proteins in the complex stress response network of E. coli.
Phadtare
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Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Inouye
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D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism*; D009997:Osmotic Pressure; D033902:Periplasmic Binding Proteins; D010544:Peroxidases / Q000235:genetics; D020871:RNA Stability; D012329:RNA, Bacterial / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012808:Sigma Factor / Q000096:biosynthesis; D027981:Symporters
D001426:Bacterial Proteins; D002352:Carrier Proteins; C088099:CspC protein, bacteria; C088097:CspE protein, E coli; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D033902:Periplasmic Binding Proteins; C079244:ProP protein, E coli; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012808:Sigma Factor; D027981:Symporters; C490241:cspC protein, E coli; C069567:sigma factor KatF protein, Bacteria; C078564:universal stress protein A, Bacteria; C074783:osmY protein, E coli; D010544:Peroxidases; C076136:catalase HPI