A protein kinase inhibitor as an antimycobacterial agent

Abstract

The protein kinase inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) was found to inhibit the growth of two different mycobacterial strains, the slow-growing Mycobacterium bovis Bacille Calmette Guerin (BCG) and the fast-growing saprophyte Mycobacterium smegmatis mc 2 155, in a dose-dependent manner. While screening for the effect of kinase inhibitors on mycobacterial growth, millimolar concentrations of H7 induced a 40% decrease in the growth of M. bovis BCG when measured as a function of oxidative phosphorylation. This H7-induced decrease in growth was shown to involve a 2-log fold decrease in the viable counts of M. smegmatis within a 48-h period and a 50% reduction in the number of BCG viable counts within a 10-day period. Micromolar concentrations of H7 compound induced a significant decrease in the activity of the Mycobacterium tuberculosis protein serine/threonine kinase (PSTK) PknB. The inhibition of mycobacterial growth as well as the inhibition of a representative M. tuberculosis protein serine/threonine kinase PknB suggests that conventional PSTK inhibitors can be used to study the role that the mycobacterial PSTK family plays in controlling bacterial growth. ß

High-throughput screening for inhibitors of Mycobacterium tuberculosis H37Rv

“…Among these mechanisms, the potential to target the bacterial enzyme inosine monophosphate dehydrogenase (IMPDH) is an area that is actively being pursued 91. Although a purely speculative connection, substituted ureas are known to compete into ATP binding sites of human kinases,92-94 and bacterial signaling kinases and ATP binding proteins are receiving increased attention as new drug targets against tuberculosis 95-98…”

PknH, a transmembrane Hank's type serine/threonine kinase fromMycobacterium tuberculosisis differentially expressed under stress conditions

“…The effect of two protein kinase inhibitors, staurosporine and H-7 [11,18], was examined on in vitro protein phosphorylation. Pre-incubation of these inhibitors with the GST-PknH inhibited its kinase activity in a dose-dependent manner with complete inhibition of kinase activity in the presence of 0.1 mM staurosporine or 10 lM H-7 (Fig.…”

Apparent growth phase-dependent phosphorylation of malonyl coenzyme A:acyl carrier protein transacylase (MCAT), a major fatty acid synthase II component inMycobacterium bovisBCG

“…The tubercle bacillus genome project revealed the presence of a large number of candidate protein kinases and phosphatases [3]. However, their substrates and hence their regulatory functions are unknown [4–13]. In a first attempt to identify substrates of these enzymes, we report here the characterization of growth phase‐dependent proteome phosphorylation in Mycobacterium bovis BCG employing anti‐phospho amino acid‐specific antibodies and the identification of an apparent protein kinase/phosphatase substrate in the tubercle bacillus.…”