Cellular signaling pathways and transcriptional regulation in Mycobacterium tuberculosis: Stress control and virulence

Mycobacterium tuberculosis is a successful pathogen that overcomes the numerous challenges presented by the immune system of the host. This bacterium usually establishes a chronic infection in the lun g where it may silently persist inside a granuloma until a failure in host defenses can lead to the reactivation of the disease. An increasing number of molecular genetic tools available in the past few years have made possible the study of signal transduction and transcriptional regulatory mechanisms that contribute to the ability of M. tuberculosis to be so well adapted. This review intends to summarize the current knowledge about the major molecular components involved in signaling pathways and in transcription al regula tion in M. tuberculosis with specific emphasis on their relation to bacterial pathogenesis and the ability to cope with stresses inside the host.