Mycobacterial protein tyrosine kinase, PtkA phosphorylates PtpA at tyrosine residues and the mechanism is stalled by the novel series of inhibitors

Abstract

Phosphorylation and dephosphorylation are the key mechanisms for mycobacterial physiology and play critical roles in mycobacterial survival and in its pathogenesis. Mycobacteria evade host immune mechanism by inhibiting phagosome – lysosome fusion in which mycobacterial protein tyrosine phosphatase A (PtpA;TP) plays an indispensable role. Tyrosine kinase (PtkA;TK) activated by autophosphorylation; phosphorylates TP, which subsequently leads to increase in its phosphatase activity. The phosphorylated TP is secreted in phagosome of macrophage. In the present study, we have shown that the phosphorylation at two sites of TP; Y¹²⁸ and Y¹²⁹ are critical for TK-mediated phosphatase activity. The disruption of this interaction between TK and TP inhibits activation of later which further leads to the decrease in intracellular survival of mycobacteria. Furthermore, the proof of concept has been established using benzylbenzofurans and benzofuranamides, which inhibit the growth and intracellular survival of mycobacteria, associate with the functional sites of TP and contend with the TK. This binding was further restated by looking at the anchorage of protein–protein and the protein–inhibitor complexes in the homology-based structure models and by surface plasmon resonance analysis.

Keywords:

• Tyrosine kinase
• tyrosine phosphatase
• mycobacteria
• benzylbenzofurans
• benzofuranamides

Acknowledgements

We thank Director, CSIR-CDRI for encouragement and support. We thank Dr. Amit Singh (IISC) for providing the pML 523 vector. The CSIR-CDRI communication number allotted to this manuscript is 9682.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work has been funded through CEFIPRA (5303-2) and Splendid (BSC0104) projects.