Borkovich, Katherine A. and Kaplan, Nachum and Hess, J. Fred and Simon, Melvin I. (1989) Transmembrane Signal Transduction in Bacterial Chemotaxis Involves Ligand-Dependent Activation of Phosphate Group Transfer. Proceedings of the National Academy of Sciences of the United States of America, 86 (4). pp. 1208-1212. ISSN 0027-8424 http://resolver.caltech.edu/CaltechAUTHORS:BORpnas89
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Signal transduction in Escherichia coli involves the interaction of transmembrane receptor proteins such as the aspartate receptor, Tar, and the products of four chemotaxis genes, cheA, cheY, cheW, and cheZ. It was previously shown that the cheA gene product is an autophosphorylating protein kinase that transfers phosphate to CheY, whereas the cheZ gene product acts as a specific CheY phosphatase. Here we report that the system can be reconstituted in vitro and receptor function can be coupled to CheY phosphorylation. Coupling requires the presence of the CheW protein, the appropriate form of the receptor, and the CheA and CheY proteins. Under these conditions the accumulation of CheY-phosphate is enhanced approx 300-fold. This rate enhancement is seen in reactions using wild-type and "tumble" mutant receptors but not "smooth" mutant receptors. The increased accumulation of phosphoprotein was inhibited by micromolar concentrations of aspartate, using wild-type, but not tumble, receptors. These results provide evidence that the signal transduction pathway in bacterial chemotaxis involves receptor-mediated alteration of the levels of phosphorylated proteins. They suggest that CheW acts as the coupling factor between receptor and phosphorylation. The results also support the suggestion that CheY-phosphate is the tumble signal.
|Additional Information:||Copyright © 1989 by the National Academy of Sciences. Contributed by Melvin I. Simon, November 21, 1988. We thank Robert Bourret, Janis Lem, Ryn Miake-Lye, and Andrew Pakula for critical reading of the manuscript and many helpful discussions. This work was supported by Grant IA 19296 from the National Institutes of Health (to M.I.S.), by National Research Service Award Fellowship GM11223-03 (to K.A.B.), and by Damon-Runyon-Walter Winchell Cancer Fund Fellowship DRG-915 (to J.F.H.). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.|
|Subject Keywords:||excitation; reconstitution; receptor; chemotaxis proteins; aspartate|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
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|Deposited On:||21 Jun 2008|
|Last Modified:||26 Dec 2012 10:07|
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