Structural highlights
Function
SAV1_MOUSE 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 (By similarity).[1] [2]
Publication Abstract from PubMed
The canonical mammalian Hippo pathway contains a core kinase signaling cascade requiring upstream MST to form a stable complex with SAV1 in order to phosphorylate the downstream LATS/MOB complex. Though SAV1 dimerization is essential for the trans-activation of MST, the molecular mechanism underlying SAV1 dimerization is unclear. Here, we discover that the SAV1 WW tandem containing a short Pro-rich extension immediately following the WW tandem (termed as "WW12ex") forms a highly stable homodimer. The crystal structure of SAV1 WW12ex reveals that the Pro-rich extension of one subunit binds to both WW domains from the other subunit. Thus, SAV1 WW12ex forms a domain-swapped dimer instead of a WW2 homodimerization-mediated dimer. The WW12ex-mediated dimerization of SAV1 is required for the MST/SAV1 complex assembly and MST kinase activation. Finally, we show that several cancer-related SAV1 variants disrupt SAV1 dimer formation, and thus, these mutations may impair the tumor-suppression activity of SAV1.
A WW Tandem-Mediated Dimerization Mode of SAV1 Essential for Hippo Signaling.,Lin Z, Xie R, Guan K, Zhang M Cell Rep. 2020 Sep 8;32(10):108118. doi: 10.1016/j.celrep.2020.108118. PMID:32905778[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lee JH, Kim TS, Yang TH, Koo BK, Oh SP, Lee KP, Oh HJ, Lee SH, Kong YY, Kim JM, Lim DS. A crucial role of WW45 in developing epithelial tissues in the mouse. EMBO J. 2008 Apr 23;27(8):1231-42. doi: 10.1038/emboj.2008.63. Epub 2008 Mar 27. PMID:18369314 doi:http://dx.doi.org/10.1038/emboj.2008.63
- ↑ Lu L, Li Y, Kim SM, Bossuyt W, Liu P, Qiu Q, Wang Y, Halder G, Finegold MJ, Lee JS, Johnson RL. Hippo signaling is a potent in vivo growth and tumor suppressor pathway in the mammalian liver. Proc Natl Acad Sci U S A. 2010 Jan 26;107(4):1437-42. doi:, 10.1073/pnas.0911427107. Epub 2010 Jan 4. PMID:20080689 doi:http://dx.doi.org/10.1073/pnas.0911427107
- ↑ Lin Z, Xie R, Guan K, Zhang M. A WW Tandem-Mediated Dimerization Mode of SAV1 Essential for Hippo Signaling. Cell Rep. 2020 Sep 8;32(10):108118. PMID:32905778 doi:10.1016/j.celrep.2020.108118
