Protein Kinase B (PknB) of Mycobacterium tuberculosis Is Essential for Growth of the Pathogen in Vitro as well as for Survival within the Host

Abstract

Background: Mycobacterium tuberculosis PknB plays a critical role in modulating cell division and cell wall synthesis. Results: We present a comprehensive evaluation of the importance of various domains of PknB in modulating cell survival. Conclusion:The intracellular kinase domain and extracytoplasmic PASTA domains of PknB are essential for cell survival. Significance: PknB is essential for both in vitro growth and survival of the pathogen in vivo.

Protein Kinase A (PknA) of Mycobacterium tuberculosis Is Independently Activated and Is Critical for Growth in Vitro and Survival of the Pathogen in the Host

“…Cells were pelleted down, resuspended in 5 ml of fixative, and kept at 4°C for 1 h, followed by overnight incubation at room temperature. Fixed cells were processed, and scanning electron microscopy images were obtained at 20,000 ϫ using a Carl Zeiss Evo LS scanning electron microscope, as described earlier (24).…”

“…To determine the ability of the anti-p-PknA antibodies to specifically detect PknA expressed in mycobacteria, WCLs from mc 2 ⌬pknA::pNit, mc 2 ⌬pknA::pNit-PknA, mc 2 ⌬pknA:: pNit-PknA K42M , and mc 2 ⌬pknA::pNit-PknA TATA were probed with anti-PknA, anti-GroEL1, anti-PknB, and anti-p-PknA antibodies. To determine the influence of PknB on loop phosphorylation of PknA, WCLs prepared from H37Rv or Rv-pptr-B (23,24) in the presence or absence of inducer pristinamycin were probed with anti-PknA, anti-GroEL1, anti-PknB, and anti-pPknA antibodies.…”

“…Based on transposon mutagenesis, both PknA and PknB have been thought to be essential (22). Although PknB has been demonstrated to be essential both for in vitro growth and in vivo survival (23,24), to date, there are no reports addressing the question of whether PknA is essential for growth or survival.…”

Regulation of transcription by eukaryotic-like serine-threonine kinases and phosphatases in Gram-positive bacterial pathogens

“…4 However, most subsequent studies have focused on these signaling cascades as being indispensable for virulence in a variety of human pathogens. [5][6][7][8][9][10][11][12][13][14][15] The 'genomic age' has revealed a considerable expansion of the eSTK protein family and the presence of their cognate eSTPs in most prokaryotic Phylums, which include important Gram-negative human pathogens such as Pseudomonas aeruginosa, 9,16 and many Gram-positives such as Enterococcus faecalis, 17 Staphylococcus aureus, 12,14,[18][19][20] Mycobacterium tuberculosis, 6,21,22 Streptococcus pneumoniae, 7,23,24 Streptococcus agalactiae 8 and Streptococcus pyogenes. 10,25 This discovery led to the realization that unlike TCS histidine kinases, which almost exclusively target a single response regulator partner, eSTK substrates are instead quite pleiotropic in nature.…”

Rv2744c Is a PspA Ortholog That Regulates Lipid Droplet Homeostasis and Nonreplicating Persistence in Mycobacterium tuberculosis

“…SigE is an extracytoplasmic function sigma factor that controls a regulon of Ͼ70 genes in response to a variety of cell envelopeperturbing agents (19,20). Finally, PknB is a serine-threonine protein kinase that regulates cell envelope stress resistance through posttranslational modifications (phosphorylation) of target substrates (21,22). Recent evidence indicates that the stressresponsive pathways controlled by MprAB, SigE, and PknB are integrated at multiple levels.…”