Suppressing host pyroptosis by a ubiquitin-activated phospholipid phosphatase of Mycobacterium tuberculosis

Tuberculosis (TB) is a major public health problem that causes millions of deaths in humans around the world, and the bacterial pathogen Mycobacterium tuberculosis (Mtb) is responsible for this disease. Evidence suggested that the inflammasome-pyroptosis pathway is crucial for preventing Mtb infection. Uncertainty exists regarding whether and how these infections can bypass this immune system by Mtb. A recent Science article by Chai et al. (doi: 10.1126/science.abq0132) revealed a novel role by a eukaryotic-like effector called PtpB during Mtb infection. The PtpB functions as a phospholipid phosphatase suppressing gasdermin D (GSDMD) dependent pyroptosis. And notably, the phospholipid phosphatase activity of PtpB is dependent on binding with mono-ubiquitin (Ub) of the host.