New drug targets for Mycobacterium tuberculosis

In spite of the availability of effective chemotherapy and Bacille-Calmette-Guerin (BCG) vaccine, tuberculosis remains a leading infectious killer world-wide. Many factors such as, human immunodeficiency virus (HIV) co-infection, drug resistance, lack of patient compliance with chemotherapy, delay in diagnosis, variable efficacy of BCG vaccine and various other factors contribute to the mortality due to tuberculosis. In spite of the new advances in understanding the biology of Mycobacterium tuberculosis, and availability of functional genomic tools, such as microarray and proteomics, in combination with modern approaches, no new drug has been developed in the past 30 yr. Therefore, there is an urgent need to identify new drug targets in mycobacteria and eventually, develop new drugs. The release of the complete genome sequence of M. tuberculosis has facilitated a more rational, and directional approach to search for new drug targets. In general, gene products involved in mycobacterial metabolism, persistence, transcription, cell wall synthesis and virulence would be possible targets for the development of new drugs. The exploitation of host cell signaling pathways for the benefit of the pathogen is a phenomenon that deserves to be looked into with a new perspective in the current scenario to combat M. tuberculosis. Reversible phosphorylation and dephosphorylation, which are carried out by specific protein kinases and phosphatases have been shown to modify the host proteins and help in the establishment of disease by several pathogenic bacteria. In this review, we discuss some possible drug targets for M. tuberculosis.