title: PknH, a transmembrane Hank's type serine/threonine kinase from Mycobacterium tuberculosis is differentially expressed under stress conditions.
abstract: Serine/threonine protein kinases (STPKs) represent a burgeoning concept in prokaryotic signaling and have been implicated in a range of control mechanisms. This paper describes the enzymatic and molecular characterization of PknH, a mycobacterial STPK. After cloning and expression as a Glutathione-S-transferase fusion protein in E. coli, PknH was found to phosphorylate itself and exogenous substrates like myelin basic protein and histone. The kinase activity of PknH was inhibited by the kinase inhibitors staurosporine and H-7. The results confirmed that PknH is a transmembrane protein and is restricted to members of the Mycobacterium tuberculosis complex. In addition, transcriptional analysis of pknH in M. tuberculosis under various stress conditions revealed that exposure to low pH and heat shock decreased the level of pknH transcription significantly. This is the first report describing differential expression of a mycobacterial kinase in response to stress conditions which can indicate its ability to regulate cellular events promoting bacterial adaptation to environmental change.
authors.affiliation: Institute of Genomics and Integrative Biology, Mall Road, Near Jubilee Hall, Delhi 110 007, India.
authors.forename: Kirti
authors.initials: K
authors.lastname: Sharma
authors.forename: Harish
authors.initials: H
authors.lastname: Chandra
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Gupta
authors.forename: Monika
authors.initials: M
authors.lastname: Pathak
authors.forename: Azeet
authors.initials: A
authors.lastname: Narayan
authors.forename: Laxman S
authors.initials: LS
authors.lastname: Meena
authors.forename: Rochelle C J
authors.initials: RC
authors.lastname: D'Souza
authors.forename: Puneet
authors.initials: P
authors.lastname: Chopra
authors.forename: S
authors.initials: S
authors.lastname: Ramachandran
authors.forename: Yogendra
authors.initials: Y
authors.lastname: Singh
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D000143:Acids; D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006657:Histones / Q000378:metabolism; D006358:Hot Temperature; D008565:Membrane Proteins / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics*; D004676:Myelin Basic Protein / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D019311:Staurosporine / Q000494:pharmacology
chemical_list: D000143:Acids; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D006657:Histones; D008565:Membrane Proteins; D004676:Myelin Basic Protein; D011993:Recombinant Fusion Proteins; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C484411:PknH protein, Mycobacterium tuberculosis; D017346:Protein Serine-Threonine Kinases; D019311:Staurosporine