title: Post-translational modification of proteins by reversible phosphorylation in prokaryotes.
abstract: Microorganisms have developed three different systems for catalyzing protein phosphorylation and using this reversible modificaiton to regulate their cellular activities. The first 'classical' system utilizes nucleoside-triphosphates as phosphoryl donors and leads to the modification of protein substrates at serine/threonine or tyrosine residues. The second system, called 'two-component system', requires first a sensor kinase which autophosphorylates at a histidine residue at the expense of adenosine-triphosphate, then a response regulator which is modified in turn at an aspartate residue and thereafter induces a metabolic change within the cell. The third system, called 'PTS system', makes use of phosphoenol pyruvate to generate a phosphoryl group which is passed down a chain of several proteins and finally transferred to a sugar. There is increasing evidence that, contrary to an early concept, these systems and the corresponding enzymes (protein kinases and phosphoprotein phosphatases) share a number of structural and functional similarities with the phosphorylation-dephosphorylation machineries found in eukaryotes. Therefore one can expect that microorganisms will serve, once again, as a basic model for exploring and understanding a key regulatory mechanism, reversible protein phosphorylation, which concerns all organisms.
authors.affiliation: Institut de Biologie et Chimie des Protéines, CNRS, Lyon, France.
authors.forename: A J
authors.initials: AJ
authors.lastname: Cozzone
mesh_terms: D000818:Animals; D010766:Phosphorylation; D011387:Prokaryotic Cells; D011494:Protein Kinases / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000378:metabolism*
chemical_list: D011506:Proteins; D011494:Protein Kinases