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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^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.