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The global regulatory system Csr senses glucose through the phosphoenolpyruvate: carbohydrate phosphotransferase system
Author(s) -
PérezMorales Deyanira,
Bustamante Víctor H.
Publication year - 2016
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13285
Subject(s) - pep group translocation , biology , adenylate kinase , phosphotransferase , phosphoenolpyruvate carboxykinase , cyclase , response regulator , biochemistry , phosphorylation , catabolite repression , regulator , microbiology and biotechnology , gene , receptor , mutant
Summary A novel connection between two regulatory systems controlling crucial biological processes in bacteria, the carbon storage regulator ( C sr) system and the glucose‐specific phosphotransferase system ( PTS ), is reported by L eng et al . in this issue. This involves the interaction of unphosphorylated EIIA Glc , a component of the glucose‐specific PTS , with the C sr D protein, which accelerates the decay of the C sr B and C sr C small RNAs via RN ase E in E scherichia coli . As unphosphorylated EIIA G lc is generated in the presence of glucose, the PTS thus acts as a sensor of glucose for the C sr system. Interestingly, another pathway can operate for communication between the C sr system and the glucose‐specific PTS . The absence of glucose generates phosphorylated EIIA Glc , which activates the enzyme adenylate cyclase to produce cyclic adenosine monophosphate ( cAMP ) that, in turn, binds to the regulator cAMP receptor protein ( CRP ). L eng et al . show that the complex cAMP – CRP modestly reduces C sr B decay independently of C sr D . On the other hand, a previous study indicates that the complex cAMP – CRP positively regulates the transcription of C sr B and C sr C in S almonella enterica . Therefore, EIIA G lc could work as a molecular switch that regulates the activity of the C sr system, in response to its phosphorylation state determined by the presence or absence of glucose, in order to control gene expression.