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Smurf1 polyubiquitinates on K285/K282 of the kinases Mst1/2 to attenuate their tumor-suppressor functions

Sterile 20–like kinases Mst1 and Mst2 (Mst1/2) and large tumor suppressor 1/2 are core kinases to mediate Hippo signaling in maintaining tissue homeostasis. We have previously demonstrated that Smad ubiquitin (Ub) regulatory factor 1 (Smurf1), a HECT-type E3 ligase, ubiquitinates and in turn destabi...

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Detalles Bibliográficos
Autores principales: Xu, Yana, Qu, Meiyu, He, Yangxun, He, Qiangqiang, Shen, Tingyu, Luo, Jiahao, Tan, Dan, Bao, Hangyang, Xu, Chengyun, Ji, Xing, Hu, Xinhua, Barkat, Muhammad Qasim, Zeng, Ling-Hui, Wu, Ximei
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10696403/
http://dx.doi.org/10.1016/j.jbc.2023.105395
Descripción
Sumario:Sterile 20–like kinases Mst1 and Mst2 (Mst1/2) and large tumor suppressor 1/2 are core kinases to mediate Hippo signaling in maintaining tissue homeostasis. We have previously demonstrated that Smad ubiquitin (Ub) regulatory factor 1 (Smurf1), a HECT-type E3 ligase, ubiquitinates and in turn destabilizes large tumor suppressor 1/2 to induce the transcriptional output of Hippo signaling. Here, we unexpectedly find that Smurf1 interacts with and polyubiquitinates Mst1/2 by virtue of K27- and K29-linked Ub chains, resulting in the proteasomal degradation of Mst1/2 and attenuation of their tumor-suppressor functions. Among the potential Ub acceptor sites on Mst1/2, K285/K282 are conserved and essential for Smurf1-induced polyubiquitination and degradation of Mst1/2 as well as transcriptional output of Hippo signaling. As a result, K285R/K282R mutation of Mst1/2 not only negates the transcriptional output of Hippo signaling but enhances the tumor-suppressor functions of Mst1/2. Together, we demonstrate that Smurf1-mediated polyubiquitination on K285/K282 of Mst1/2 destabilizes Mst1/2 to attenuate their tumor-suppressor functions. Thus, the present study identifies Smurf1-mediated ubiquitination of Mst1/2 as a hitherto uncharacterized mechanism fine-tuning the Hippo signaling pathway and may provide additional targets for therapeutic intervention of diseases associated with this important pathway.