title: 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.
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis, #1, Mayor Sathiyamoorthy road, Chetpet, Chennai, 600 031, India. Electronic address: refayanasar@gmail.com.
authors.forename: Ahmed Kabir
authors.initials: AK
authors.lastname: Refaya
authors.affiliation: National JALMA Institute for Leprosy & other Mycobacterial Diseases, Taj Ganj, Agra 282004, India. Electronic address: divakarsharma88@gmail.com.
authors.forename: Divakar
authors.initials: D
authors.lastname: Sharma
authors.affiliation: National JALMA Institute for Leprosy & other Mycobacterial Diseases, Taj Ganj, Agra 282004, India. Electronic address: vksJalma@gmail.com.
authors.forename: Virendra
authors.initials: V
authors.lastname: Kumar
authors.affiliation: National JALMA Institute for Leprosy & other Mycobacterial Diseases, Taj Ganj, Agra 282004, India. Electronic address: abd1109@rediffmail.com.
authors.forename: Deepa
authors.initials: D
authors.lastname: Bisht
authors.affiliation: Department of Immunology, National Institute for Research in Tuberculosis, #1, Mayor Sathiyamoorthy road, Chetpet, Chennai, 600 031, India. Electronic address: sujatha.sujatha36@gmail.com.
authors.forename: Sujatha
authors.initials: S
authors.lastname: Narayanan
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D050296:Microbial Viability / Q000187:drug effects; D008855:Microscopy, Electron, Scanning; D009113:Muramidase / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020543:Proteome / Q000032:analysis; D034622:RNA Interference; D012967:Sodium Dodecyl Sulfate / Q000633:toxicity; D013312:Stress, Physiological
chemical_list: D020543:Proteome; D012967:Sodium Dodecyl Sulfate; D017346:Protein Serine-Threonine Kinases; D009113:Muramidase
keywords: 2D gel electrophoresis; Adaptive response; Antisense; PknL; SEM