MST4 Antibody #3822

Mammalian sterile-20-like (MST) kinases are upstream regulators of mitogen-activated protein kinase (MAPK) signaling pathways that regulate multiple biological processes, including apoptosis, morphogenesis, cell migration, and cytoskeletal rearrangements (1). This group of serine/threonine kinases includes a pair of closely related proteins (MST1, MST2) that are functionally distinct from the more distantly related MST3 and MST4 kinases. All four MST kinases share a conserved amino-terminal kinase domain and carboxy-terminal regulatory and interaction domains (1-3). At least three of these kinases (MST1-3) promote apoptosis and are activated by caspase cleavage followed by nuclear translocation of the active kinase. MST1/2 kinases play a key role in the Hippo signaling pathway, an evolutionarily conserved program that controls organ size by regulating cell proliferation, apoptosis, and stem cell self renewal (4).
Mammalian Sterile 20-like kinase 4 (MST4, STK26, MASK) is a Golgi-localized kinase that is cleaved by caspase-3 in vitro. While its potential role in apoptosis is unclear, research studies indicate that MST4 is involved in MAPK and EGF pathway signaling (5,6). MST4 and the serine/threonine kinase YSK1 (STK25) localize to the Golgi apparatus following association with the Golgi scaffold protein GM130. Binding to GM130 activates MST4 through autophosphorylation at Thr178 (7).