Phosphoprotein phosphatase of Mycobacterium tuberculosis dephosphorylates serine-threonine kinases PknA and PknB.
The regulation of cellular processes by the modulation of protein phosphorylation/dephosphorylation is fundamental to a large number of processes in living organisms. These processes are carried out by specific protein kinases and phosphatases. In this study, a previously uncharacterized gene (Rv0018c) of Mycobacterium tuberculosis, designated as mycobacterial Ser/Thr phosphatase (mstp), was cloned, expressed in Escherichia coli, and purified as a histidine-tagged protein. Purified protein (Mstp) dephosphorylated the phosphorylated Ser/Thr residues of myelin basic protein (MBP), histone, and casein but failed to dephosphorylate phospho-tyrosine residue of these substrates, suggesting that this phosphatase is specific for Ser/Thr residues. It has been suggested that mstp is a part of a gene cluster that also includes two Ser/Thr kinases pknA and pknB. We show that Mstp is a trans-membrane protein that dephosphorylates phosphorylated PknA and PknB. Southern blot analysis revealed that mstp is absent in the fast growing saprophytes Mycobacterium smegmatis and Mycobacterium fortuitum. PknA has been shown, whereas PknB has been proposed to play a role in cell division. The presence of mstp in slow growing mycobacterial species, its trans-membrane localization, and ability to dephosphorylate phosphorylated PknA and PknB implicates that Mstp may play a role in regulating cell division in M. tuberculosis.
Chopra
Puneet
P
Institute of Genomics and Integrative Biology, Mall Road, Delhi, India.
Singh
Bhuminder
B
Singh
Ramandeep
R
Vohra
Reena
R
Koul
Anil
A
Meena
Laxman S
LS
Koduri
Harshavardhan
H
Ghildiyal
Megha
M
Deol
Parampal
P
Das
Taposh K
TK
Tyagi
Anil K
AK
Singh
Yogendra
Y
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013379:Substrate Specificity; D014018:Tissue Distribution
D001426:Bacterial Proteins; C451020:PknA protein, Mycobacterium tuberculosis; C475060:PknB protein, Mycobacterium tuberculosis; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases