Abstract
Whether the Hippo pathway has downstream targets other than YAP and TAZ is unknown. In this report, we have identified angiomotin (Amot) family members as novel substrates of Hippo core kinases. The N-terminal regions of Amot proteins contain a conserved HXRXXS consensus site for LATS1/2-mediated phosphorylation. Phospho-specific antibodies showed that Hippo core kinases could mediate phosphorylation of endogenous as well as exogenous Amot family members. Knockdown of LATS1 and LATS2 endogenously reduced the phosphorylation of Amots detected by the phospho-specific antibodies. Mutation of the serine to alanine within this HXRXXS site in Amot and AmotL2 established that this site was essential for Hippo core kinase-mediated phosphorylation. Wild-type and non-phosphorylated Amot (Amot-S175A) were targeted to actin filaments, whereas phospho-mimic Amot (Amot-S175D) failed to be localized with actin. Overexpression of LATS2 caused dissociation of Amot from actin but not Amot-S175A. Mapping of the actin-binding site of Amot showed that serine 175 of Amot was important for the actin-binding activity. Amot-S175A promoted, whereas Amot and Amot-S175D inhibited, cell proliferation. These results collectively suggest that the Hippo pathway negatively regulates the actin-binding activity of Amot family members through direct phosphorylation.
Highlights
LATS kinase, one of the core kinases of Hippo pathway, phosphorylates and inactivates the downstream coactivator YAP/TAZ
Because the signaling pathway is generally known to have a feedback mechanism, it is possible that the Hippo core kinase complex phosphorylates other components of the Hippo pathway besides YAP and TAZ
This analysis revealed that Amot and angiomotin-like 2 (AmotL2) have a single HXRXXS motif, whereas angiomotin-like 1 (AmotL1) has three such motifs (Fig. 1A)
Summary
LATS kinase, one of the core kinases of Hippo pathway, phosphorylates and inactivates the downstream coactivator YAP/TAZ. Results: The angiomotin (Amot) family members are phosphorylated by LATS kinase. Conclusion: Phosphorylation of Amots by LATS kinase inhibits actin-binding, stabilizes Amot, and inhibits cell proliferation. We have identified angiomotin (Amot) family members as novel substrates of Hippo core kinases. Phospho-specific antibodies showed that Hippo core kinases could mediate phosphorylation of endogenous as well as exogenous Amot family members. Mutation of the serine to alanine within this HXRXXS site in Amot and AmotL2 established that this site was essential for Hippo core kinase-mediated phosphorylation. Amot-S175A promoted, whereas Amot and Amot-S175D inhibited, cell proliferation These results collectively suggest that the Hippo pathway negatively regulates the actin-binding activity of Amot family members through direct phosphorylation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
