PHI-1, an Endogenous Inhibitor Protein for Protein Phosphatase-1 and a Pan-Cancer Marker, Regulates Raf-1 Proteostasis.
PHI-1, an Endogenous Inhibitor Protein for Protein Phosphatase-1 and a Pan-Cancer Marker, Regulates Raf-1 Proteostasis.
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DOI：
10.3390/biom13121741
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发表时间：
2023-12-04
期刊：
影响因子：
5.5
通讯作者：
中科院分区：
文献类型：
--
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Raf-1是一种多功能激酶，通过磷酸化MAPK/ERK激酶并与特异性激酶相互作用来调节多种细胞过程，包括细胞增殖、凋亡和迁移。细胞Raf-1活性通过涉及调节蛋白的结合、直接磷酸化和泛素-蛋白酶体轴的途径被复杂地调节。在这项研究中，我们证明，PHI-1，蛋白磷酸酶-1（PP 1）的内源性抑制剂，在调节细胞内Raf-1蛋白稳态中起着关键作用。使用siRNA敲低HEK 293细胞中的内源性PHI-1导致细胞增殖增加和细胞凋亡减少。这种细胞增殖的增加伴随着ERK 1/2磷酸化的15倍增加。重要的是，所观察到的ERK 1/2过度磷酸化归因于Raf-1表达的上调，而不是Ras水平、Raf-1 Ser 338磷酸化或B-Raf水平的增加。Raf-1表达的升高，源于PHI-1敲低，增强EGF诱导的ERK 1/2磷酸化通过MEK。此外，PHI-I敲低显著有助于Raf-1蛋白的稳定性，而不影响Raf-1 mRNA水平。相反，异位PHI-1表达抑制Raf-1蛋白水平的方式与PHI-1的抑制效力。使用互变霉素抑制PP 1以模拟PHI-1的功能导致Raf-1表达的减少。总之，我们的研究结果强调，PHI-1-PP 1信号轴选择性地管理Raf-1蛋白质稳态和细胞存活信号。
Raf-1, a multifunctional kinase, regulates various cellular processes, including cell proliferation, apoptosis, and migration, by phosphorylating MAPK/ERK kinase and interacting with specific kinases. Cellular Raf-1 activity is intricately regulated through pathways involving the binding of regulatory proteins, direct phosphorylation, and the ubiquitin–proteasome axis. In this study, we demonstrate that PHI-1, an endogenous inhibitor of protein phosphatase-1 (PP1), plays a pivotal role in modulating Raf-1 proteostasis within cells. Knocking down endogenous PHI-1 in HEK293 cells using siRNA resulted in increased cell proliferation and reduced apoptosis. This heightened cell proliferation was accompanied by a 15-fold increase in ERK1/2 phosphorylation. Importantly, the observed ERK1/2 hyperphosphorylation was attributable to an upregulation of Raf-1 expression, rather than an increase in Ras levels, Raf-1 Ser338 phosphorylation, or B-Raf levels. The elevated Raf-1 expression, stemming from PHI-1 knockdown, enhanced EGF-induced ERK1/2 phosphorylation through MEK. Moreover, PHI-1 knockdown significantly contributed to Raf-1 protein stability without affecting Raf-1 mRNA levels. Conversely, ectopic PHI-1 expression suppressed Raf-1 protein levels in a manner that correlated with PHI-1’s inhibitory potency. Inhibiting PP1 to mimic PHI-1’s function using tautomycin led to a reduction in Raf-1 expression. In summary, our findings highlight that the PHI-1-PP1 signaling axis selectively governs Raf-1 proteostasis and cell survival signals.
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DOI：
10.1540/jsmr.58.22
发表时间：
2022
期刊：
Journal of smooth muscle research = Nihon Heikatsukin Gakkai kikanshi
影响因子：
--
作者：
Eto, Masumi;Katsuki, Shuichi;Ohashi, Minami;Miyagawa, Yui;Tanaka, Yoshinori;Takeya, Kosuke;Kitazawa, Toshio
通讯作者：
Kitazawa, Toshio
影响因子：
4.8
作者：
Broustas, CG;Grammatikakis, N;Kasid, U
通讯作者：
Kasid, U
影响因子：
15.3
作者：
Kolbus, A;Pilat, S;Baccarini, M
通讯作者：
Baccarini, M
影响因子：
2.3
作者：
Kim, Jee In;Young, Garbo D.;Eto, Masumi
通讯作者：
Eto, Masumi
影响因子：
5.5
作者：
Kitazawa, T;Polzin, AN;Eto, M
通讯作者：
Eto, M