Eleanor Bagg - Specificity of localization and phosphotransfer in the CheA proteins of Rhodobacter sphaeroides

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  Publication Details (including relevant citation   information):

  Mol Microbiol 2010 76(2):318-30.


  Specificity of protein-protein interactions plays a vital role in   signal transduction. The chemosensory pathway of Rhodobacter   sphaeroides comprises multiple homologues of chemotaxis proteins   characterized in organisms such as Escherichia coli. Three CheA   homologues are essential for chemotaxis in R. sphaeroides under   laboratory conditions. These CheAs are differentially localized   to two chemosensory clusters, one at the cell pole and one in the   cytoplasm. The polar CheA, CheA(2), has the same domain structure   as E. coli CheA and can phosphorylate all R. sphaeroides   chemotaxis response regulators. CheA(3) and CheA(4) independently   localize to the cytoplasmic cluster; each protein has a subset of   the CheA domains, with CheA(3) phosphorylating CheA(4) together   making a functional CheA protein. Interestingly, CheA(3)-P can   only phosphorylate two response regulators, CheY(6) and CheB(2).   R. sphaeroides CheAs exhibit two interesting differences in   specificity: (i) the response regulators that they phosphorylate   and (ii) the chemosensory cluster to which they localize. Using a   domain-swapping approach we investigated the role of the P1 and   P5 CheA domains in determining these specificities. We show that   the P1 domain is sufficient to determine which response   regulators will be phosphorylated in vitro while the P5 domain is   sufficient to localize the CheAs to a specific chemosensory   cluster.

  Address (URL): http://www3.interscience.wiley.com/journal/123318892/abstract?CRETRY=1&SRETRY=0