Caspase-mediated cleavage of Mst3 activates its intrinsic kinase activity. Proteolytic removal of the COOH-terminal domain promotes nuclear translocation of its kinase domain. Ectopic expression of COOH-terminal truncated Mst3 results in DNA fragmentation and morphological changes characteristic of apoptosis (Huang et al., 2002). Both CASP3 and CASP7 can cleave MST3, and phosphorylation of MST3 may promote facilitate caspase-mediated cleavage (Turowec et al. 2014).