A Serine/threonine kinase PknL , is involved in the adaptive response of Mycobacterium tuberculosis

Abstract

Mycobacterium tuberculosis adapts itself to various environmental stress conditions to thrive inside the phagosome for establishing a chronic infection. Serine/threonine protein kinases (STPKs) play a major role in the physiology and pathogenesis of Mycobacterium tuberculosis. Some of these STPKs are involved in regulating the growth of the mycobacterium under nutrient stress and starvation conditions. In this study, we have investigated the role of PknL, a STPK in the adaptive responses of M. tuberculosis by conditional inactivation of the gene using antisense technology. The inhibition of PknL in the knockdown strain was validated by RT-PCR. The in vitro growth kinetics of M. tuberculosis strain following inhibition of PknL was found to be bacteriostatic. The knock down strain of PknL exhibited a better survival in pH 5.5 when compared to its growth in pH 7.0. Similarly, it also exhibited more resistance to both SDS(0.01%) and Lysozyme stress (2.5mg/ml), indicating that loss of PknL enhances the growth of mycobacterium under stress conditions. SEM pictographs also represent an increase in the cell length of the knock down strain compared to Wild type stressing its role in cellular integrity. Lastly, the proteome analysis of differentially expressing PknL strains by 2D gel electrophoresis and mass spectrometry identified 19 differentially expressed proteins. Our findings have shown that PknL plays an important role in sensing the host environment and adapting itself in slowing down the growth of the pathogen and persisting within the host.

Multisystem Analysis of Mycobacterium tuberculosis Reveals Kinase-Dependent Remodeling of the Pathogen-Environment Interface

“…Expression of five of these genes in our transcriptomic data was not consistent with PknD inhibition. In a pknL knockdown strain, 7 proteins were highly expressed compared to the wild-type results ( 25 ); in our kinase inhibition data, none of these showed significantly increased expression.…”

A Serine/Threonine Kinase PknL is required For the Persistence of Mycobacterium tuberculosis

“…Serine/threonine kinases are generally involved in detecting and responding to the immediate changes in the environment through phosphorylation/dephosphorylation activity and we have already reported the role of PknL in the adaptive response of M. tuberculosis under the influence of environmental stress [11]. We extended our study in investigating the role of PknL in starvation survival response which may contribute to the The data is representative of three independent experiments.…”

“…We have previously generated mutant strains of PknL by antisense strategy in an IPTG inducible system and have also reported that this gene is involved in the adaptive response of Mycobacterium tuberculosis [11]. In this study, we have used the same constructs to determine its role in starvation survival response of the pathogen along with the wild type H 37 Rv.…”

Tetrahymena thermophila Predation Enhances Environmental Adaptation of the Carp Pathogenic Strain Aeromonas hydrophila NJ-35

“…For example, serine/threonine protein kinases (STPKs) have been shown to be involved in stress responses in prokaryotes (Av-Gay and Everett, 2000 ). The inactivation of pknE, pknI, pknK , or pknL , which encode STPKs in Mycobacterium tuberculosis , resulted in an increased survival in response to an acidic pH, oxidative pressure, and the presence of lysozyme and antibiotics (Gopalaswamy et al, 2009 ; Malhotra et al, 2010 ; Kumar et al, 2013 ; Refaya et al, 2016 ). Consistent with this, a Stpk protein was detected to be down-regulated in the SCVs.…”