STK3, Serine/threonine-protein kinase 3
Enzyme Classification 126.96.36.199
Also Known as
STK3_HUMAN, STK3, KRS1, MST2
Stress-activated, pro-apoptotic kinase which, following caspase-cleavage, enters the nucleus and induces chromatin condensation followed by internucleosomal DNA fragmentation. Key component of the Hippo signaling pathway which plays a pivotal role in organ size control and tumor suppression by restricting proliferation and promoting apoptosis. The core of this pathway is composed of a kinase cascade wherein STK3/MST2 and STK4/MST1, in complex with its regulatory protein SAV1, phosphorylates and activates LATS1/2 in complex with its regulatory protein MOB1, which in turn phosphorylates and inactivates YAP1 oncoprotein and WWTR1/TAZ. Phosphorylation of YAP1 by LATS2 inhibits its translocation into the nucleus to regulate cellular genes important for cell proliferation, cell death, and cell migration. STK3/MST2 and STK4/MST1 are required to repress proliferation of mature hepatocytes, to prevent activation of facultative adult liver stem cells (oval cells), and to inhibit tumor formation. Phosphorylates NKX2-1 (By similarity). Phosphorylates NEK2 and plays a role in centrosome disjunction by regulating the localization of NEK2 to centrosome, and its ability to phosphorylate CROCC and CEP250. In conjunction with SAV1, activates the transcriptional activity of ESR1 through the modulation of its phosphorylation. Positively regulates RAF1 activation via suppression of the inhibitory phosphorylation of RAF1 on 'Ser-259'. Phosphorylates MOBKL1A and RASSF2. Phosphorylates MOBKL1B on 'Thr-74'. Acts cooperatively with MOBKL1B to activate STK38. Homodimer; mediated via the coiled-coil region. Interacts with NORE1, which inhibits autoactivation (By similarity). Interacts with and stabilizes SAV1 (PubMed:15688006, PubMed:16930133, PubMed:28087714). Interacts with RAF1, which prevents dimerization and phosphorylation. Interacts with RASSF1. Interacts (via SARAH domain) with isoform 1 of NEK2. Interacts with ESR1 only in the presence of SAV1. Interacts with PKB/AKT1. Forms a tripartite complex with MOBKL1B and STK38. Interacts with RASSF2 (via SARAH domain). Interacts with DLG5 (via PDZ domain 3) (PubMed:28087714). Interacts with LATS1; this interaction is inhibited in the presence of DLG5 (PubMed:28087714). Interacts with MARK3 in the presence of DLG5 (PubMed:28087714).