Q13043, Q13188

The mammalian Ste20-like kinases (MST) also known as KRS proteins are members of the GCK subfamily. MST are upstream regulators of mitogen-activated protein kinase (MAPK) signaling pathways that regulate multiple cellular processes, including proliferation, apoptosis, migration, and cytoskeletal rearrangement. This family of serine/threonine kinases includes MST1 (KRS2) and MST2 (KRS1), two functionally related proteins with conserved amino-terminal kinase domains and carboxy-terminal regulatory domains that contain nuclear export signals. During apoptosis, caspase-mediated cleavage of MST1/2 removes the inhibitory regulatory domain, triggering autophosphorylation and activation of the kinase domain, which is translocated to the nucleus. Nuclear translocation of the active kinase induces chromatin condensation and other events associated with apoptotic progression.