Antimicrobial Activity of Quinazolin Derivatives of 1,2-Di(quinazolin-4-yl)diselane against Mycobacteria.

Mycobacterium tuberculosis (M. tuberculosis) is one of the leading causes of morbidity and mortality. Currently, the emergence of drug resistance has an urgent need for new drugs. In previous study, we found that 1,2-di(quinazolin-4-yl)diselane (DQYD), a quinazoline derivative, has anticancer activities against many cancers. However, whether DQYD has the activity of antimycobacterium is still little known. Here our results show that DQYD has a similar value of the minimum inhibitory concentration with clinical drugs against mycobacteria and also has the ability of bacteriostatic activity with dose-dependent and time-dependent manner. Furthermore, the activities of DQYD against M. tuberculosis are associated with intracellular ATP homeostasis. Meanwhile, mycobacterium DNA damage level was increased after DQYD treatment. But there was no correlation between survival of mycobacteria in the presence of DQYD and intercellular reactive oxygen species. This study enlightens the possible benefits of quinazoline derivatives as potential antimycobacterium compounds and furtherly suggests a new strategy to develop new methods for searching antituberculosis drugs.

An internal EELD domain facilitates mitochondrial targeting of Mcl-1 via a Tom70-dependent pathway.

Mcl-1 functions at an apical step in many regulatory programs that control cell death. Although the mitochondrion is one major subcellular organelle where Mcl-1 functions, the molecular mechanism by which Mcl-1 is targeted to mitochondria remains unclear. Here, we demonstrate that Mcl-1 is loosely associated with the outer membrane of mitochondria. Furthermore, we demonstrate that Mcl-1 interacts with the mitochondrial import receptor Tom70, and such interaction requires an internal domain of Mcl-1 that contains an EELD motif. A Tom70 antibody that blocks Mcl-1-Tom70 interaction blocks mitochondrial import of Mcl-1 in vitro. Furthermore, Mcl-1 is significantly less targeted to mitochondria in Tom70 knockdown than in the control cells. Similar targeting preference is also observed for the DM mutant of Mcl-1 whose mutation at the EELD motif markedly attenuates its Tom70 binding activity. Together, our results indicate that the internal EELD domain facilitates mitochondrial targeting of Mcl-1 via a Tom70-dependent pathway.