Signal transduction pathways in response to protein misfolding in the extracytoplasmic compartments of E. coli: role of two new phosphoprotein phosphatases PrpA and PrpB.
It is now well established that the sigmaE regulon of Escherichia coli is induced by misfolding of proteins in the periplasm and the outer membrane. htrA belongs to this regulon and encodes a periplasmic protease involved in the degradation of misfolded proteins. htrA transcription is also under the positive control of a two component signal transduction system CpxR CpxA. Closer examination of the putative signal transduction pathway modulating htrA transcription has led us to the identification of two new genes. Biochemical and genetic evidence shows that these two genes encode two phosphoprotein phosphatases, designated PrpA and PrpB. These are the first examples of typical serine/threonine and tyrosine phosphatases described in E. coli. PrpA and PrpB are involved in signaling protein misfolding via the CpxR CpxA transducing system. In addition, both PrpA and PrpB modulate the phosphorylated status of some other phosphoproteins in E. coli. Finally, we show that PrpA is a heat shock protein.
Missiakas
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Centre Medical Universitaire, Departement de Biochimie Medicale, Geneve, Switzerland.
Raina
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D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D001483:Base Sequence; D002462:Cell Membrane / Q000201:enzymology; D017124:Conserved Sequence; D017931:DNA Primers; D004330:Drosophila; D004926:Escherichia coli / Q000201:enzymology*; D015723:Gene Library; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics
D001426:Bacterial Proteins; D017931:DNA Primers; D006360:Heat-Shock Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C063202:sporulation-specific sigma factors; D010749:Phosphoprotein Phosphatases