title: Role of Mycobacterium tuberculosis Ser/Thr kinase PknF: implications in glucose transport and cell division.
abstract: Protein kinases have a diverse array of functions in bacterial physiology, with a distinct role in the regulation of development, stress responses, and pathogenicity. pknF, one of the 11 kinases of Mycobacterium tuberculosis, encodes an autophosphorylating, transmembrane serine/threonine protein kinase, which is absent in the fast-growing, nonpathogenic Mycobacterium smegmatis. Herein, we investigate the physiological role of PknF using an antisense strategy with M. tuberculosis and expressing PknF and its kinase mutant (K41M) in M. smegmatis. Expression of PknF in M. smegmatis led to reduction in the growth rate and shortening and swelling of cells with constrictions. Interestingly, an antisense strain of M. tuberculosis expressing a low level of PknF displayed fast growth and a deformed cell morphology compared to the wild-type strain. Electron microscopy showed that most of the cells of the antisense strain were of a smaller size with an aberrant septum. Furthermore, nutrient transport analysis of these strains was conducted using 3H-labeled and 14C-labeled substrates. A significant increase in the uptake of D-glucose but not of glycerol, leucine, or oleic acid was observed in the antisense strain compared to the wild-type strain. The results suggest that PknF plays a direct/indirect role in the regulation of glucose transport, cell growth, and septum formation in M. tuberculosis.
authors.affiliation: Institute of Genomics and Integrative Biology, Mall Road, Delhi, India.
authors.forename: Parampal
authors.initials: P
authors.lastname: Deol
authors.forename: Reena
authors.initials: R
authors.lastname: Vohra
authors.forename: Adesh Kumar
authors.initials: AK
authors.lastname: Saini
authors.forename: Amit
authors.initials: A
authors.lastname: Singh
authors.forename: Harish
authors.initials: H
authors.lastname: Chandra
authors.forename: Puneet
authors.initials: P
authors.lastname: Chopra
authors.forename: Taposh K
authors.initials: TK
authors.lastname: Das
authors.forename: Anil K
authors.initials: AK
authors.lastname: Tyagi
authors.forename: Yogendra
authors.initials: Y
authors.lastname: Singh
mesh_terms: D002250:Carbon Radioisotopes; D002455:Cell Division / Q000502:physiology; D002473:Cell Wall / Q000648:ultrastructure; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D020102:Mycobacterium smegmatis / Q000166:cytology / Q000201:enzymology / Q000254:growth & development; D009169:Mycobacterium tuberculosis / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D016372:RNA, Antisense; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D016372:RNA, Antisense; D014316:Tritium; C487814:PknF protein, Mycobacterium tuberculosis; D017346:Protein Serine-Threonine Kinases; D005947:Glucose