Figure 1. FIGURE 1: Cytokinin synthesis in M. tuberculosis.

(A) M. tuberculosis Log is tightly regulated by the mycobacterial proteasome to maintain low amounts of the protein. In a proteolysis-deficient mutant, Log accumulates and results in elevated cytokinin levels, the breakdown of which into aldehydes kills mycobacteria in the presence of NO produced by macrophages.

(B) To date, the role of cytokinins in M. tuberculosis infection is unknown. Cytokinins may be used as signaling molecules to communicate among mycobacteria (i) and/or act on the host (ii, iii) in order to establish a successful infection.