Tumor suppressor p27Kip1 undergoes endolysosomal degradation through its interaction with sorting nexin 6
Tumor suppressor p27Kip1 undergoes endolysosomal degradation through its interaction with sorting nexin 6
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DOI：
10.1096/fj.09-138255
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发表时间：
2010-08-01
期刊：
影响因子：
4.8
通讯作者：
Andres, Vicente
中科院分区：
文献类型：
--
作者：
Fuster, Jose J.;Gonzalez, Jose M.;Andres, Vicente
大量证据支持生长抑制因子 p27(Kip1) (p27) 的蛋白酶体降解促进哺乳动物细胞周期进展的假设。然而，很少有研究探讨 p27 蛋白水解的独立于蛋白酶体的机制的可能性。在这里，我们提供了 p27 通过溶酶体降解的新途径的证据，该途径是通过溶酶体与内体蛋白分选 nexin 6 (SNX6) 的相互作用介导的，SNX6 是囊泡运输调节因子分选 nexin 家族的成员。 p27 和 SNX6 在哺乳动物细胞中体外和体内相互作用，部分共定位于内涵体中，并且存在于纯化的内涵体级分中。功能获得和丧失研究表明，SNX6 诱导 p27 在内体积累。此外，p27 在溶酶体中被检测到，并且溶酶体依赖性蛋白水解的抑制会以 SNX6 依赖性方式损害血清介导的 p27 下调。为了验证 p27 在这些细胞器中的定位，我们使用两种不同的抗 p27 抗体、几种细胞器特异性标记 [例如早期内体抗原 1、溶酶体相关膜蛋白 (LAMP) 1、LAMP2 和 LysoTracker] 以及荧光 p27 和 SNX6 的过表达，分析了几种细胞系。值得注意的是，SNX6 的沉默会减弱有丝分裂细胞周期 G(1) 期 p27 的下调并延迟细胞周期进程。因此，我们得出的结论是，除了蛋白酶体依赖性途径外，SNX6 介导的 p27 内溶酶体降解也有助于哺乳动物细胞的细胞周期进展。-Fuster, J. J.、Gonzalez, J. M.、Edo, M. D.、Viana, R.、Boya, P.、Cervera, J.、Verges, M.、Rivera, J.、Andres, V. 肿瘤抑制因子p27(Kip1) 通过与分选连接蛋白 6 相互作用而经历内溶酶体降解。FASEB J. 24, 2998-3009 (2010)。 www.fasebj.org
A large body of evidence supports the hypothesis that proteasomal degradation of the growth suppressor p27(Kip1) (p27) facilitates mammalian cell cycle progression. However, very few studies have addressed the possibility of proteasome-independent mechanisms of p27 proteolysis. Here we provide evidence for a novel pathway of p27 degradation via the lysosome that is mediated by its interaction with the endosomal protein sorting nexin 6 (SNX6), a member of the sorting nexin family of vesicular trafficking regulators. p27 and SNX6 interact in vitro and in vivo in mammalian cells, partially colocalize in endosomes, and are present in purified endosomal fractions. Gain-and loss-of-function studies revealed that SNX6 induces endosomal accumulation of p27. Moreover, p27 is detected in lysosomes and inhibition of lysosome-dependent proteolysis impairs serum-mediated down-regulation of p27 in a SNX6-dependent manner. To validate the localization of p27 in these organelles, we analyzed several cell lines using two different anti-p27 antibodies, several organelle-specific markers [e.g., early endosome antigen 1, lysosomal-associated membrane protein (LAMP) 1, LAMP2, and LysoTracker], and overexpression of fluorescent p27 and SNX6. Remarkably, silencing of SNX6 attenuates p27 down-regulation in the G(1) phase of the mitotic cell cycle and delays cell cycle progression. We therefore conclude that, in addition to the proteasome-dependent pathway, SNX6-mediated endolysosomal degradation of p27 also contributes to cell cycle progression in mammalian cells.-Fuster, J. J., Gonzalez, J. M., Edo, M. D., Viana, R., Boya, P., Cervera, J., Verges, M., Rivera, J., Andres, V. Tumor suppressor p27(Kip1) undergoes endolysosomal degradation through its interaction with sorting nexin 6. FASEB J. 24, 2998-3009 (2010). www.fasebj.org