title: The ATPase ClpX is conditionally involved in the morphological differentiation of Streptomyces lividans.
abstract: ATP-dependent proteases of the ClpP type are widespread in eubacteria. These proteolytic complexes are composed of a proteolytic subunit and an ATPase subunit. They are involved in the degradation of denatured proteins, but also play a role in specific regulatory pathways. In Streptomyces lividans strains which lack the proteolytic subunit ClpP1, cell cycle progression has been shown to be blocked at early stages of growth. In this study, we examined the role of the ATPase subunit ClpX, a possible partner of the products of the clpP1 operon. A clpX mutant was obtained and it was shown that its growth was impaired only on acidic medium. Thus, the clpX phenotype differs from the clpP1 phenotype, indicating that these two components have only partially overlapping roles. We also analyzed the expression of clpX. Although clpX expression is increased under heat-shock conditions in many bacteria, we found that this is not the case in S. lividans.
authors.affiliation: Unité de Biochimie Microbienne, Institut Pasteur, 25 rue du Docteur Roux, 75724 Cedex 15, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Viala
authors.forename: P
authors.initials: P
authors.lastname: Mazodier
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D002453:Cell Cycle; D049071:Endopeptidase Clp; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D013302:Streptomyces / Q000166:cytology / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; C119657:ClpP1 protein, Streptomyces coelicolor; D012697:Serine Endopeptidases; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C088072:ClpX protein, E coli; D000074183:ATPases Associated with Diverse Cellular Activities