Mouse Anti-STK4 Recombinant Antibody (CBXS-1148) (CBMAB-S4030-CQ)

serine/threonine kinase 4

The protein encoded by this gene is a cytoplasmic kinase that is structurally similar to the yeast Ste20p kinase, which acts upstream of the stress-induced mitogen-activated protein kinase cascade. The encoded protein can phosphorylate myelin basic protein and undergoes autophosphorylation. A caspase-cleaved fragment of the encoded protein has been shown to be capable of phosphorylating histone H2B. The particular phosphorylation catalyzed by this protein has been correlated with apoptosis, and it's possible that this protein induces the chromatin condensation observed in this process.

KRS2; MST1; YSK3

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 (By similarity).
Phosphorylates 'Ser-14' of histone H2B (H2BS14ph) during apoptosis. Phosphorylates FOXO3 upon oxidative stress, which results in its nuclear translocation and cell death initiation. Phosphorylates MOBKL1A, MOBKL1B and RASSF2. Phosphorylates TNNI3 (cardiac Tn-I) and alters its binding affinity to TNNC1 (cardiac Tn-C) and TNNT2 (cardiac Tn-T). Phosphorylates FOXO1 on 'Ser-212' and regulates its activation and stimulates transcription of PMAIP1 in a FOXO1-dependent manner. Phosphorylates SIRT1 and inhibits SIRT1-mediated p53/TP53 deacetylation, thereby promoting p53/TP53 dependent transcription and apoptosis upon DNA damage. Acts as an inhibitor of PKB/AKT1. Phosphorylates AR on 'Ser-650' and suppresses its activity by intersecting with PKB/AKT1 signaling and antagonizing formation of AR-chromatin complexes.

Biological Process apoptotic processManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process branching involved in blood vessel morphogenesisIEA:Ensembl
Biological Process canonical Wnt signaling pathwayIEA:Ensembl
Biological Process cell differentiation involved in embryonic placenta developmentIEA:Ensembl
Biological Process cell morphogenesisManual Assertion Based On ExperimentIDA:MGI
Biological Process central nervous system developmentIEA:Ensembl
Biological Process endocardium developmentIEA:Ensembl
Biological Process epithelial cell proliferationIEA:Ensembl
Biological Process extrinsic apoptotic signaling pathway via death domain receptorsIEA:Ensembl
Biological Process hepatocyte apoptotic processIEA:Ensembl
Biological Process hippo signalingManual Assertion Based On ExperimentIDA:BHF-UCL
Biological Process intracellular signal transductionManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process keratinocyte differentiationIEA:Ensembl
Biological Process negative regulation of canonical Wnt signaling pathwayManual Assertion Based On ExperimentIMP:BHF-UCL
Biological Process negative regulation of epithelial cell proliferationIEA:Ensembl
Biological Process negative regulation of organ growthIEA:Ensembl
Biological Process neural tube formationIEA:Ensembl
Biological Process organ growthIEA:Ensembl
Biological Process peptidyl-serine phosphorylationManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process positive regulation of apoptotic processManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process positive regulation of extrinsic apoptotic signaling pathway via death domain receptorsIEA:Ensembl
Biological Process positive regulation of fat cell differentiationIEA:Ensembl
Biological Process positive regulation of hepatocyte apoptotic processIEA:Ensembl
Biological Process positive regulation of peptidyl-serine phosphorylationManual Assertion Based On ExperimentIDA:MGI
Biological Process positive regulation of protein bindingManual Assertion Based On ExperimentIDA:MGI
Biological Process positive regulation of protein phosphorylationManual Assertion Based On ExperimentIDA:MGI
Biological Process positive regulation of substrate-dependent cell migration, cell attachment to substrateIEA:Ensembl
Biological Process primitive hemopoiesisIEA:Ensembl
Biological Process protein autophosphorylationManual Assertion Based On ExperimentIDA:MGI
Biological Process protein import into nucleusManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process protein phosphorylationManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process protein stabilizationManual Assertion Based On ExperimentIDA:MGI
Biological Process protein tetramerizationIEA:InterPro
Biological Process regulation of cell differentiation involved in embryonic placenta developmentIEA:Ensembl
Biological Process regulation of MAPK cascadeManual Assertion Based On ExperimentIBA:GO_Central
Biological Process signal transductionManual Assertion Based On ExperimentTAS:ProtInc

Cytoplasm
Nucleus
The caspase-cleaved form cycles between the nucleus and cytoplasm.

T-cell immunodeficiency, recurrent infections, and autoimmunity with or without cardiac malformations (TIIAC):
A primary T-cell immunodeficiency syndrome characterized by progressive loss of naive T-cells, recurrent bacterial, viral, and fungal infections, warts, and abscesses, autoimmune manifestations, and cardiac malformations, including atrial septal defect.

Autophosphorylated on serine and threonine residues. Phosphorylation at Thr-387 by PKB/AKT1, leads to inhibition of its: kinase activity, nuclear translocation and autophosphorylation at Thr-183. It also diminishes its cleavage by caspases and its ability to phosphorylate FOXO3.
Proteolytically cleaved by caspase-3 during apoptosis at Asp-326 and Asp-349 resulting in a 37 kDa or a 39 kDa subunit respectively. The 39 kDa subunit is further cleaved into the 37 kDa form. Proteolytic cleavage results in kinase activation and nuclear translocation of the truncated form (MST1/N). It is less likely that cleavage at Asp-349 is a prerequisite for activation as this site is not conserved in the murine ortholog.