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HupB, a Nucleoid-Associated Protein of Mycobacterium tuberculosis, Is Modified by Serine/Threonine Protein Kinases In Vivo

Gupta, Meetu and Sajid, Andaleeb and Sharma, Kirti and Ghosh, Soumitra and Arora, Gunjan and Singh, Ramandeep and Nagaraja, Valakunja and Tandon, Vibha and Singh, Yogendra (2014) HupB, a Nucleoid-Associated Protein of Mycobacterium tuberculosis, Is Modified by Serine/Threonine Protein Kinases In Vivo. In: JOURNAL OF BACTERIOLOGY, 196 (14). pp. 2646-2657.

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Official URL: http://dx.doi.org/10.1128/JB.01625-14


HU, a widely conserved bacterial histone-like protein, regulates many genes, including those involved in stress response and virulence. Whereas ample data are available on HU-DNA communication, the knowledge on how HU perceives a signal and transmit it to DNA remains limited. In this study, we identify HupB, the HU homolog of the human pathogen Mycobacterium tuberculosis, as a component of serine/threonine protein kinase (STPK) signaling. HupB is extracted in its native state from the exponentially growing cells of M. tuberculosis H37Ra and is shown to be phosphorylated on both serine and threonine residues. The STPKs capable of modifying HupB are determined in vitro and the residues modified by the STPKs are identified for both in vivo and the in vitro proteins through mass spectrometry. Of the identified phosphosites, Thr(65) and Thr(74) in the DNA-embracing beta-strand of the N-terminal domain of HupB (N-HupB) are shown to be crucial for its interaction with DNA. In addition, Arg(55) is also identified as an important residue for N-HupB-DNA interaction. N-HupB is shown to have a diminished interaction with DNA after phosphorylation. Furthermore, hupB is shown to be maximally expressed during the stationary phase in M. tuberculosis H37Ra, while HupB kinases were found to be constitutively expressed (PknE and PknF) or most abundant during the exponential phase (PknB). In conclusion, HupB, a DNA-binding protein, with an ability to modulate chromatin structure is proposed to work in a growth-phase-dependent manner through its phosphorylation carried out by the mycobacterial STPKs.

Item Type: Journal Article
Additional Information: copyright for this article belongs to AMER SOC MICROBIOLOGY,USA
Department/Centre: Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited: 19 Aug 2014 11:25
Last Modified: 19 Aug 2014 11:25
URI: http://eprints.iisc.ac.in/id/eprint/49630

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