Functional characterization of lysosomal interaction of Akt with VRK2.
Functional characterization of lysosomal interaction of Akt with VRK2.
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DOI：
10.1038/s41388-018-0330-0
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发表时间：
2018-10
期刊：
影响因子：
8
通讯作者：
Noguchi M
中科院分区：
文献类型：
--
作者：
Hirata N;Suizu F;Matsuda-Lennikov M;Tanaka T;Edamura T;Ishigaki S;Donia T;Lithanatudom P;Obuse C;Iwanaga T;Noguchi M
丝氨酸-苏氨酸激酶Akt（也称为PKB，蛋白激酶B）是细胞存活的核心细胞内介质，涉及多种人类癌症，并且已经被认为在哺乳动物细胞中的自噬调节中起重要作用。然而，Akt在溶酶体中的生理功能目前尚不清楚。我们以前曾报道过PtdIns（3）P依赖性的Akt-Phafin 2复合物在溶酶体中的积累是自噬诱导的关键步骤。在这里，为了表征自噬过程中溶酶体中激活的Akt的分子功能，我们寻找在诱导自噬后与溶酶体中的Akt复合物相互作用的分子。通过飞行时间质谱（TOF/MS）分析，鉴定了VRK家族的激酶，VRK家族是人类激酶组中独特的丝氨酸-苏氨酸激酶家族。VRK 2与Akt 1和Akt 2相互作用，但不与Akt 3相互作用;在哺乳动物细胞中，Akt的C末端和VRK 2的N末端促进Akt和VRK 2的相互作用。在免疫共沉淀试验中，VRK 2A的激酶死亡形式（KD VRK 2A）未能与Akt相互作用。双分子荧光互补（BiFC）实验表明，在溶酶体中，Akt与VRK 2A相互作用，而与VRK 2B或KDVRK 2A不相互作用。免疫荧光检测显示，自噬诱导后，VRK 2和磷酸化Akt在溶酶体中积累。WT VRK 2A，而不是KD VRK 2A或VRK 2B，促进磷酸化Akt在溶酶体中的积累。VRK 2的下调废除了磷酸化Akt的溶酶体积累和TFEB的核定位受损;这些事件与自噬诱导的抑制相一致。VRK 2-Akt复合物是控制溶酶体大小、酸化、细菌降解和病毒复制所必需的。此外，溶酶体VRK 2-Akt控制细胞增殖和线粒体外膜稳定。鉴于自噬在人类癌症发病机制中的作用，目前的研究提供了一个新的见解，通过调节自噬，在溶酶体中的VRK 2-Akt复合物的致癌活性。
Serine–threonine kinase Akt (also known as PKB, protein kinase B), a core intracellular mediator of cell survival, is involved in various human cancers and has been suggested to play an important role in the regulation of autophagy in mammalian cells. Nonetheless, the physiological function of Akt in the lysosomes is currently unknown. We have reported previously that PtdIns(3)P-dependent lysosomal accumulation of the Akt–Phafin2 complex is a critical step for autophagy induction. Here, to characterize the molecular function of activated Akt in the lysosomes in the process of autophagy, we searched for the molecules that interact with the Akt complex at the lysosomes after induction of autophagy. By time-of-flight–mass spectrometry (TOF/MS) analysis, kinases of the VRK family, a unique serine–threonine family of kinases in the human kinome, were identified. VRK2 interacts with Akt1 and Akt2, but not with Akt3; the C terminus of Akt and the N terminus of VRK2 facilitate the interaction of Akt and VRK2 in mammalian cells. The kinase-dead form of VRK2A (KD VRK2A) failed to interact with Akt in coimmunoprecipitation assays. Bimolecular fluorescence complementation (BiFC) experiments showed that, in the lysosomes, Akt interacted with VRK2A but not with VRK2B or KD VRK2A. Immunofluorescent assays revealed that VRK2 and phosphorylated Akt accumulated in the lysosomes after autophagy induction. WT VRK2A, but not KD VRK2A or VRK2B, facilitated accumulation of phosphorylated Akt in the lysosomes. Downregulation of VRK2 abrogated the lysosomal accumulation of phosphorylated Akt and impaired nuclear localization of TFEB; these events coincided to inhibition of autophagy induction. The VRK2–Akt complex is required for control of lysosomal size, acidification, bacterial degradation, and for viral replication. Moreover, lysosomal VRK2–Akt controls cellular proliferation and mitochondrial outer-membrane stabilization. Given the roles of autophagy in the pathogenesis of human cancer, the current study provides a novel insight into the oncogenic activity of VRK2–Akt complexes in the lysosomes via modulation of autophagy.
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DOI：
10.1126/science.1201940
发表时间：
2011-08-26
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Green DR;Galluzzi L;Kroemer G
通讯作者：
Kroemer G
影响因子：
3.7
作者：
BANHAM, AH;SMITH, GL
通讯作者：
SMITH, GL
影响因子：
64.5
作者：
Green DR;Levine B
通讯作者：
Levine B
影响因子：
5.4
作者：
Fredericksen, BL;Wei, BL;Garcia, JV
通讯作者：
Garcia, JV
DOI：
10.1083/jcb.143.1.65
发表时间：
1998-10-05
期刊：
The Journal of cell biology
影响因子：
--
作者：
Gary JD;Wurmser AE;Bonangelino CJ;Weisman LS;Emr SD
通讯作者：
Emr SD