Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 284, Issue 17, Pages 11090-11099Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M808705200
Keywords
-
Categories
Funding
- Department of Biotechnology India
- Council of Scientific and Industrial Research [NWP-0038]
Ask authors/readers for more resources
Mycobacterium tuberculosis encodes for 11 eukaryotic-like serine/threonine protein kinases. Genetic and biochemical studies show that these kinases regulate various cellular processes including cell shape and morphology, glucose and glutamine transport, phagosome-lysosome fusion and the expression, and/or activity of transcription factors. PknK is the largest predicted serine/threonine protein kinase in M. tuberculosis. Here, we have cloned, overexpressed, and purified protein kinaseK(PknK) to near homogeneity and show that its ability to phosphorylate proteins is dependent on the invariant lysine (Lys(55)), and on two conserved threonine residues present in its activation loop. Despite being devoid of any apparent transmembrane domain, PknK is localized to the cell wall fraction, suggesting probable anchoring of the kinase to the cell membrane region. The pknK gene is located in the vicinity of the virS gene, which is known to regulate the expression of the mycobacterial monooxygenase (mymA) operon. We report here for the first time that VirS is in fact a substrate of PknK. In addition, four of the proteins encoded by mymA operon are also found to be substrates of PknK. Results show that VirS is a bona fide substrate of PknK in vivo, and PknK-mediated phosphorylation of VirS increases its affinity for mym promoter DNA. Reporter assays reveal that PknK modulates VirS-mediated stimulation of transcription from the mym promoter. These findings suggest that the expression of mymA operon genes is regulated through PknK-mediated phosphorylation of VirS.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available