title: HupB, a nucleoid-associated protein of Mycobacterium tuberculosis, is modified by serine/threonine protein kinases in vivo.
abstract: 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 β-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.
authors.affiliation: CSIR-Institute of Genomics and Integrative Biology, Delhi, India.
authors.forename: Meetu
authors.initials: M
authors.lastname: Gupta
authors.affiliation: CSIR-Institute of Genomics and Integrative Biology, Delhi, India.
authors.forename: Andaleeb
authors.initials: A
authors.lastname: Sajid
authors.affiliation: Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany.
authors.forename: Kirti
authors.initials: K
authors.lastname: Sharma
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
authors.forename: Soumitra
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: CSIR-Institute of Genomics and Integrative Biology, Delhi, India.
authors.forename: Gunjan
authors.initials: G
authors.lastname: Arora
authors.affiliation: Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, Haryana, India.
authors.forename: Ramandeep
authors.initials: R
authors.lastname: Singh
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
authors.forename: Valakunja
authors.initials: V
authors.lastname: Nagaraja
authors.affiliation: Department of Chemistry, University of Delhi, Delhi, India.
authors.forename: Vibha
authors.initials: V
authors.lastname: Tandon
authors.affiliation: CSIR-Institute of Genomics and Integrative Biology, Delhi, India ysingh@igib.res.in.
authors.forename: Yogendra
authors.initials: Y
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006657:Histones; C510666:HupB protein, Mycobacterium tuberculosis; D017346:Protein Serine-Threonine Kinases