| Structural highlights
Function
[STK3_HUMAN] 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.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [SAV1_HUMAN] Regulator of STK3/MST2 and STK4/MST1 in 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 LATS1/2 inhibits its translocation into the nucleus to regulate cellular genes important for cell proliferation, cell death, and cell migration. SAV1 is required for STK3/MST2 and STK4/MST1 activation and promotes cell-cycle exit and terminal differentiation in developing epithelial tissues. Plays a role in centrosome disjunction by regulating the localization of NEK2 to centrosomes, and its ability to phosphorylate CROCC and CEP250. In conjunction with STK3/MST2, activates the transcriptional activity of ESR1 through the modulation of its phosphorylation.[11] [12] [13] [14]
Publication Abstract from PubMed
The Hippo pathway controls tissue growth and homeostasis through a central MST-LATS kinase cascade. The scaffold protein SAV1 promotes the activation of this kinase cascade, but the molecular mechanisms remain unknown. Here, we discover SAV1-mediated inhibition of the PP2A complex STRIPAKSLMAP as a key mechanism of MST1/2 activation. SLMAP binding to autophosphorylated MST2 linker recruits STRIPAK and promotes PP2A-mediated dephosphorylation of MST2 at the activation loop. Our structural and biochemical studies reveal that SAV1 and MST2 heterodimerize through their SARAH domains. Two SAV1-MST2 heterodimers further dimerize through SAV1 WW domains to form a heterotetramer, in which MST2 undergoes trans-autophosphorylation. SAV1 directly binds to STRIPAK and inhibits its phosphatase activity, protecting MST2 activation-loop phosphorylation. Genetic ablation of SLMAP in human cells leads to spontaneous activation of the Hippo pathway and alleviates the need for SAV1 in Hippo signaling. Thus, SAV1 promotes Hippo activation through counteracting the STRIPAKSLMAP PP2A phosphatase complex.
SAV1 promotes Hippo kinase activation through antagonizing the PP2A phosphatase STRIPAK.,Bae SJ, Ni L, Osinski A, Tomchick DR, Brautigam CA, Luo X Elife. 2017 Oct 24;6. pii: e30278. doi: 10.7554/eLife.30278. PMID:29063833[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Creasy CL, Chernoff J. Cloning and characterization of a member of the MST subfamily of Ste20-like kinases. Gene. 1995 Dec 29;167(1-2):303-6. PMID:8566796
- ↑ Taylor LK, Wang HC, Erikson RL. Newly identified stress-responsive protein kinases, Krs-1 and Krs-2. Proc Natl Acad Sci U S A. 1996 Sep 17;93(19):10099-104. PMID:8816758
- ↑ Chan EH, Nousiainen M, Chalamalasetty RB, Schafer A, Nigg EA, Sillje HH. The Ste20-like kinase Mst2 activates the human large tumor suppressor kinase Lats1. Oncogene. 2005 Mar 17;24(12):2076-86. PMID:15688006 doi:1208445
- ↑ Callus BA, Verhagen AM, Vaux DL. Association of mammalian sterile twenty kinases, Mst1 and Mst2, with hSalvador via C-terminal coiled-coil domains, leads to its stabilization and phosphorylation. FEBS J. 2006 Sep;273(18):4264-76. Epub 2006 Aug 23. PMID:16930133 doi:EJB5427
- ↑ Praskova M, Xia F, Avruch J. MOBKL1A/MOBKL1B phosphorylation by MST1 and MST2 inhibits cell proliferation. Curr Biol. 2008 Mar 11;18(5):311-21. doi: 10.1016/j.cub.2008.02.006. PMID:18328708 doi:10.1016/j.cub.2008.02.006
- ↑ Hirabayashi S, Nakagawa K, Sumita K, Hidaka S, Kawai T, Ikeda M, Kawata A, Ohno K, Hata Y. Threonine 74 of MOB1 is a putative key phosphorylation site by MST2 to form the scaffold to activate nuclear Dbf2-related kinase 1. Oncogene. 2008 Jul 17;27(31):4281-92. doi: 10.1038/onc.2008.66. Epub 2008 Mar 24. PMID:18362890 doi:10.1038/onc.2008.66
- ↑ Cooper WN, Hesson LB, Matallanas D, Dallol A, von Kriegsheim A, Ward R, Kolch W, Latif F. RASSF2 associates with and stabilizes the proapoptotic kinase MST2. Oncogene. 2009 Aug 20;28(33):2988-98. doi: 10.1038/onc.2009.152. Epub 2009 Jun, 15. PMID:19525978 doi:10.1038/onc.2009.152
- ↑ Kilili GK, Kyriakis JM. Mammalian Ste20-like kinase (Mst2) indirectly supports Raf-1/ERK pathway activity via maintenance of protein phosphatase-2A catalytic subunit levels and consequent suppression of inhibitory Raf-1 phosphorylation. J Biol Chem. 2010 May 14;285(20):15076-87. doi: 10.1074/jbc.M109.078915. Epub, 2010 Mar 8. PMID:20212043 doi:10.1074/jbc.M109.078915
- ↑ Mardin BR, Lange C, Baxter JE, Hardy T, Scholz SR, Fry AM, Schiebel E. Components of the Hippo pathway cooperate with Nek2 kinase to regulate centrosome disjunction. Nat Cell Biol. 2010 Dec;12(12):1166-76. doi: 10.1038/ncb2120. Epub 2010 Nov 14. PMID:21076410 doi:10.1038/ncb2120
- ↑ Park Y, Park J, Lee Y, Lim W, Oh BC, Shin C, Kim W, Lee Y. Mammalian MST2 kinase and human Salvador activate and reduce estrogen receptor alpha in the absence of ligand. J Mol Med (Berl). 2011 Feb;89(2):181-91. doi: 10.1007/s00109-010-0698-y. Epub, 2010 Nov 23. PMID:21104395 doi:10.1007/s00109-010-0698-y
- ↑ Callus BA, Verhagen AM, Vaux DL. Association of mammalian sterile twenty kinases, Mst1 and Mst2, with hSalvador via C-terminal coiled-coil domains, leads to its stabilization and phosphorylation. FEBS J. 2006 Sep;273(18):4264-76. Epub 2006 Aug 23. PMID:16930133 doi:EJB5427
- ↑ Luo X, Li Z, Yan Q, Li X, Tao D, Wang J, Leng Y, Gardner K, Judge SI, Li QQ, Hu J, Gong J. The human WW45 protein enhances MST1-mediated apoptosis in vivo. Int J Mol Med. 2009 Mar;23(3):357-62. PMID:19212654
- ↑ Mardin BR, Lange C, Baxter JE, Hardy T, Scholz SR, Fry AM, Schiebel E. Components of the Hippo pathway cooperate with Nek2 kinase to regulate centrosome disjunction. Nat Cell Biol. 2010 Dec;12(12):1166-76. doi: 10.1038/ncb2120. Epub 2010 Nov 14. PMID:21076410 doi:10.1038/ncb2120
- ↑ Park Y, Park J, Lee Y, Lim W, Oh BC, Shin C, Kim W, Lee Y. Mammalian MST2 kinase and human Salvador activate and reduce estrogen receptor alpha in the absence of ligand. J Mol Med (Berl). 2011 Feb;89(2):181-91. doi: 10.1007/s00109-010-0698-y. Epub, 2010 Nov 23. PMID:21104395 doi:10.1007/s00109-010-0698-y
- ↑ Bae SJ, Ni L, Osinski A, Tomchick DR, Brautigam CA, Luo X. SAV1 promotes Hippo kinase activation through antagonizing the PP2A phosphatase STRIPAK. Elife. 2017 Oct 24;6. pii: e30278. doi: 10.7554/eLife.30278. PMID:29063833 doi:http://dx.doi.org/10.7554/eLife.30278
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