DISTINCT REGULATION OF AUTOPHAGIC ACTIVITY BY TWO NOVEL PROTEINS

两种新型蛋白质对自噬活性的独特调节

基本信息

批准号：
8169173
负责人：
Zhenyu Yue
金额：
$ 0.35万
依托单位：
ROCKEFELLER UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-03-01 至 2011-02-28
项目状态：
已结题

项目摘要

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Beclin 1 is a mammalian autophagy protein which was shown to play an important role in development, tumor suppression, neurodegeneration and cell death. Beclin 1 forms a complex with Vps34/phosphatidylinositol (PtdIns) 3-kinase (class III PI-3K), which mediates multiple vesicle trafficking pathways including endocytosis and autophagy. However, the precise role of Beclin 1-Vps34/PtdIns3K complex in the regulation of autophagy remains to be elucidated. Through a study that combines mouse genetics and biochemistry, we uncover several protein components that associate specifically with Beclin 1 complexes in mouse tissues. The biochemical analysis reveals a large in vivo Beclin 1 complex containing the known proteins Vps34/PtdIns3K, p150/Vps15 and UVRAG, as well as novel proteins BISC and BIRC. Characterization of the novel proteins suggests that BISC and BIRC modulate Vps34/PtdIns3K activity in opposite manner. This opposing effect of BISC and BIRC on the lipid kinase activity is correlated with their distinct regulation of autophagy: BISC positively regulates autophagy, whereas BIRC is involved in negative control of autophagy. Moreover, we find that Beclin 1 and BISC synergistically promote formation of double membrane vacuoles which are associated with Atg5/Atg12, while forced expression of BIRC results in aberrant late endosomal/lysosomal structures (independent of Beclin 1) and impaired autophagosome maturation. Our study suggests that, by forming distinct protein complexes, Beclin 1 and its binding proteins orchestrate the precise function of Vps34/PtdIns3K in regulating autophagy at multiple steps. A manuscript describing this work has been published (18. Y. Zhong, Q.J. Wang, X. Li, B.T. Chait, N. Heintz, Z. Yue "Distinct regulation of autophagic activity by Atg14L and Rubicon associated with Beclin 1-phosphatidylinositol-3-kinase complex" Nature Cell Biology. 11 (2009) 468-76.)

该子项目是利用该技术的众多研究子项目之一资源由 NIH/NCRR 资助的中心拨款提供。子项目和研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金，因此可以在其他 CRISP 条目中表示。列出的机构是对于中心来说，它不一定是研究者的机构。 Beclin 1 是一种哺乳动物自噬蛋白，已被证明在发育、肿瘤抑制、神经变性和细胞死亡中发挥重要作用。 Beclin 1 与 Vps34/磷脂酰肌醇 (PtdIns) 3-激酶（III 类 PI-3K）形成复合物，介导多种囊泡运输途径，包括内吞作用和自噬。然而，Beclin 1-Vps34/PtdIns3K 复合物在自噬调节中的确切作用仍有待阐明。通过一项结合小鼠遗传学和生物化学的研究，我们发现了几种与小鼠组织中 Beclin 1 复合物特异性相关的蛋白质成分。生化分析揭示了体内存在一个大型 Beclin 1 复合物，其中含有已知蛋白 Vps34/PtdIns3K、p150/Vps15 和 UVRAG，以及新型蛋白 BISC 和 BIRC。新蛋白质的表征表明 BISC 和 BIRC 以相反的方式调节 Vps34/PtdIns3K 活性。 BISC 和 BIRC 对脂质激酶活性的这种相反作用与其对自噬的独特调节相关：BISC 正向调节自噬，而 BIRC 参与自噬的负控制。此外，我们发现 Beclin 1 和 BISC 协同促进与 Atg5/Atg12 相关的双膜液泡的形成，而 BIRC 的强制表达会导致异常的晚期内体/溶酶体结构（独立于 Beclin 1）和受损的自噬体成熟。我们的研究表明，通过形成不同的蛋白质复合物，Beclin 1 及其结合蛋白协调 Vps34/PtdIns3K 在多个步骤中调节自噬的精确功能。描述这项工作的手稿已发表（18. Y. Zhu, Q.J. Wang, X. Li, B.T. Chait, N. Heintz, Z. Yue“Atg14L 和 Rubicon 与 Beclin 1-phosphatidylinositol-3 相关的自噬活性的独特调节” -激酶复合物”《自然细胞生物学》。11（2009）468-76。）