title: Cooperation of two distinct coupling proteins creates chemosensory network connections.
abstract: Although it is appreciated that bacterial chemotaxis systems rely on coupling, also called scaffold, proteins to both connect input receptors with output kinases and build interkinase connections that allow signal amplification, it is not yet clear why many systems use more than one coupling protein. We examined the distinct functions for multiple coupling proteins in the bacterial chemotaxis system ofHelicobacter pylori, which requires two nonredundant coupling proteins for chemotaxis: CheW and CheV1, a hybrid of a CheW and a phosphorylatable receiver domain. We report that CheV1 and CheW have largely redundant abilities to interact with chemoreceptors and the CheA kinase, and both similarly activated CheA's kinase activity. We discovered, however, that they are not redundant for formation of the higher order chemoreceptor arrays that are known to form via CheA-CheW interactions. In support of this possibility, we found that CheW and CheV1 interact with each other and with CheA independent of the chemoreceptors. Therefore, it seems that some microbes have modified array formation to require CheW and CheV1. Our data suggest that multiple coupling proteins may be used to provide flexibility in the chemoreceptor array formation.
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064.
authors.forename: Samar
authors.initials: S
authors.lastname: Abedrabbo
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064.
authors.forename: Juan
authors.initials: J
authors.lastname: Castellon
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064.
authors.forename: Kieran D
authors.initials: KD
authors.lastname: Collins
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Johnson
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064 ottemann@ucsc.edu.
authors.forename: Karen M
authors.identifier: 0000-0001-6265-7401
authors.initials: KM
authors.lastname: Ottemann
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002633:Chemotaxis / Q000502:physiology*; D000072236:Methyl-Accepting Chemotaxis Proteins / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins
keywords: chemoreceptor arrays; chemotaxis; scaffold; signal transduction