Disruption of mptpB impairs the ability of Mycobacterium tuberculosis to survive in guinea pigs.
Protein tyrosine kinases and tyrosine phosphatases from several bacterial pathogens have been shown to act as virulence factors by modulating the phosphorylation and dephosphorylation of host proteins. The identification and characterization of two tyrosine phosphatases namely MptpA and MptpB from Mycobacterium tuberculosis has been reported earlier. MptpB is secreted by M. tuberculosis into extracellular mileu and exhibits a pH optimum of 5.6, similar to the pH of the lysosomal compartment of the cell. To determine the role of MptpB in the pathogenesis of M. tuberculosis, we constructed a mptpB mutant strain by homologous recombination and compared the ability of parent and the mutant strain to survive intracellularly. We show that disruption of the mptpB gene impairs the ability of the mutant strain to survive in activated macrophages and guinea pigs but not in resting macrophages suggesting the importance of its role in the host-pathogen interaction. Infection of guinea pigs with the mutant strain resulted in a 70-fold reduction in the bacillary load of spleens in infected animals as compared with the bacillary load in animals infected with the parental strain. Upon reintroduction of the mptpB gene into the mutant strain, the complemented strain was able to establish infection and survive in guinea pigs at rates comparable to the parental strain. These observations demonstrate a role of MptpB in the pathogenesis of M. tuberculosis.
Singh
Ramandeep
R
Department of Biochemistry, University of Delhi South campus, Benito Juarez Road, New Delhi-110021, India.
Rao
Vivek
V
Shakila
H
H
Gupta
Radhika
R
Khera
Aparna
A
Dhar
Neeraj
N
Singh
Amit
A
Koul
Anil
A
Singh
Yogendra
Y
Naseema
M
M
Narayanan
P R
PR
Paramasivan
C N
CN
Ramanathan
V D
VD
Tyagi
Anil K
AK
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002478:Cells, Cultured; D005816:Genetic Complementation Test; D006168:Guinea Pigs; D006790:Host-Parasite Interactions / Q000235:genetics; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000472:pathogenicity*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000378:metabolism*; D011995:Recombination, Genetic; D013154:Spleen / Q000382:microbiology / Q000473:pathology; D014376:Tuberculosis / Q000382:microbiology / Q000473:pathology; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; C414465:MptpA protein, Mycobacterium tuberculosis; D011993:Recombinant Fusion Proteins; D017027:Protein Tyrosine Phosphatases