Organization of the receptor-kinase signaling array that regulates Escherichia coli chemotaxis.
J Biol Chem
; 277(39): 36748-54, 2002 Sep 27.
Article
em En
| MEDLINE
| ID: mdl-12119289
ABSTRACT
Motor behavior in prokaryotes is regulated by a phosphorelay network involving a histidine protein kinase, CheA, whose activity is controlled by a family of Type I membrane receptors. In a typical Escherichia coli cell, several thousand receptors are organized together with CheA and an Src homology 3-like protein, CheW, into complexes that tend to be localized at the cell poles. We found that these complexes have at least 6 receptors per CheA. CheW is not required for CheA binding to receptors, but is essential for kinase activation. The kinase activity per mole of bound CheA is proportional to the total bound CheW. Similar results were obtained with the E. coli serine receptor, Tsr, and the Salmonella typhimurium aspartate receptor, Tar. In the case of Tsr, under conditions optimal for kinase activation, the ratio of subunits in complexes is approximately 6 Tsr4 CheW1 CheA. Our results indicate that information from numerous receptors is integrated to control the activity of a relatively small number of kinase molecules.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Transdução de Sinais
/
Quimiotaxia
/
Escherichia coli
/
Proteínas de Membrana
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos