title: Regulation of RcsA by the ClpYQ (HslUV) protease in Escherichia coli.
abstract: Escherichia coli ClpYQ protease and Lon protease possess a redundant function for degradation of SulA, a cell division inhibitor. An experimental cue implied that the capsule synthesis activator RcsA, a known substrate of Lon, is probably a specific substrate for the ClpYQ protease. This paper shows that overexpression of ClpQ and ClpY suppresses the mucoid phenotype of a lon mutant. Since the cpsB (wcaB) gene, involved in capsule synthesis, is activated by RcsA, the reporter construct cpsB-lacZ was used to assay for beta-galactosidase activity and thus follow RcsA stability. The expression of cpsB-lacZ was increased in double mutants of lon in combination with clpQ or/and clpY mutation(s) compared with the wild-type or lon single mutants. Overproduction of ClpYQ or ClpQ decreased cpsB-lacZ expression. Additionally, a P(BAD)-rcsA fusion construct showed quantitatively that an inducible RcsA activates cpsB-lacZ expression. The effect of RcsA on cpsB-lacZ expression was shown to be influenced by the ClpYQ activities. Moreover, a rcsA(Red)-lacZ translational fusion construct showed higher activity of RcsA(Red)-LacZ in a clpQ clpY strain than in the wild-type. By contrast, overproduction of cellular ClpYQ resulted in decreased beta-galactosidase levels of RcsA(Red)-LacZ. Taken together, the data indicate that ClpYQ acts as a secondary protease in degrading the Lon substrate RcsA.
authors.affiliation: Department of Agricultural Chemistry, Bldg 2, R311, National Taiwan University, Taipei (106), Taiwan, ROC.
authors.forename: Mei-Shiue
authors.initials: MS
authors.lastname: Kuo
authors.affiliation: Department of Agricultural Chemistry, Bldg 2, R311, National Taiwan University, Taipei (106), Taiwan, ROC.
authors.forename: Kuei-Peng
authors.initials: KP
authors.lastname: Chen
authors.affiliation: Department of Agricultural Chemistry, Bldg 2, R311, National Taiwan University, Taipei (106), Taiwan, ROC.
authors.forename: Whi Fin
authors.initials: WF
authors.lastname: Wu
mesh_terms: D049069:ATP-Dependent Proteases; D001483:Base Sequence; D017931:DNA Primers; D049071:Endopeptidase Clp; D029968:Escherichia coli Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D005838:Genotype; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D016133:Polymerase Chain Reaction; D049070:Protease La; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism
chemical_list: C483566:ClpYQ protease, E coli; D017931:DNA Primers; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; C067572:RcsA protein, E coli; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La; D049071:Endopeptidase Clp