Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies described lacZ'- and cat'-'cpxA fusion genes whose expression restored to normal all the phenotypic defects associated with cpxA mutations (Albin, R., and Silverman, P. M. (1984) Mol. Gen. Genet. 197, 272-279). Here, we show by DNA nucleotide sequence analysis that the fusion genes encode 241 carboxyl-terminal amino acids of the CpxA polypeptide. Using this information, we constructed a fusion gene containing the same 241 cpxA codons preceded by 1007 codons of beta-galactosidase. The resultant hybrid polypeptide was purified and used to raise an anti-(CpxA polypeptide) antiserum. Using the antiserum, we have identified the chromsomal Escherichia coli K12 cpxA gene product as a 52-kDa polypeptide. The polypeptide showed temperature-sensitive accumulation in a strain carrying both the cpxA2[Ts] and cpxB1 alleles and accumulated to a level higher than normal in cells that carried a high-copy number, cpxA+ plasmid. Immune precipitates of in vitro transcription-translation reactions with cpxA+ plasmids as template also contained a 52-kDa polypeptide, indistinguishable in electrophoretic mobility from the immunoreactive polypeptide synthesized in vivo. Two regions of amino acid sequence at the carboxyl-terminus of the CpxA polypeptide are significantly homologous to corresponding regions of the E. coli K12 EnvZ polypeptide, an inner membrane component that, like the CpxA polypeptide, is required to maintain the protein composition of the cell envelope. The cpxA coding sequence is followed by two repetitive extragenic palindrome sequences in opposite orientation.
 ...
PMID:The Cpx proteins of Escherichia coli K12. Immunologic detection of the chromosomal cpxA gene product. 300 73

In a genetic screening directed to identify genes involved in biofilm formation, mutations in the cpxA gene were found to reduce biofilm formation by affecting microbial adherence to solid surfaces. This effect was detected in Escherichia coli K12 as well as in E. coli strains isolated from patients with catheter-related bacteremia. We show that the negative effect of the cpxA mutation on biofilm formation results from a decreased transcription of the curlin encoding csgA gene. The effect of the cpxA mutation could not be observed in cpxR- mutants, suggesting that they affect the same regulatory pathway. The cpxA101 mutation abolishes cpxA phosphatase activity and results in the accumulation of phosphorylated CpxR. Features of the strain carrying the cpxA101 mutation are a reduced ability to form biofilm and low levels of csgA transcription. Our results indicate that the cpxA gene increases the levels of csgA transcription by dephosphorylation of CpxR, which acts as a negative regulator at csgA. Thus, we propose the existence of a new signal transduction pathway involved in the adherence process in addition to the EnvZ-OmpR two-component system.
 ...
PMID:Involvement of the Cpx signal transduction pathway of E. coli in biofilm formation. 1048 36