Regulation of RcsA by the ClpYQ (HslUV) protease in Escherichia coli.
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.
Kuo
Mei-Shiue
MS
Department of Agricultural Chemistry, Bldg 2, R311, National Taiwan University, Taipei (106), Taiwan, ROC.
Chen
Kuei-Peng
KP
Department of Agricultural Chemistry, Bldg 2, R311, National Taiwan University, Taipei (106), Taiwan, ROC.
Wu
Whi Fin
WF
Department of Agricultural Chemistry, Bldg 2, R311, National Taiwan University, Taipei (106), Taiwan, ROC.
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
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