PknH, a transmembrane Hank's type serine/threonine kinase from Mycobacterium tuberculosis is differentially expressed under stress conditions.
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.
Sharma
Kirti
K
Institute of Genomics and Integrative Biology, Mall Road, Near Jubilee Hall, Delhi 110 007, India.
Chandra
Harish
H
Gupta
Pradeep K
PK
Pathak
Monika
M
Narayan
Azeet
A
Meena
Laxman S
LS
D'Souza
Rochelle C J
RC
Chopra
Puneet
P
Ramachandran
S
S
Singh
Yogendra
Y
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
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