Atg29 phosphorylation regulates coordination of the Atg17-Atg31-Atg29 complex with the Atg11 scaffold during autophagy initiation
Atg29 phosphorylation regulates coordination of the Atg17-Atg31-Atg29 complex with the Atg11 scaffold during autophagy initiation
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DOI：
10.1073/pnas.1300064110
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发表时间：
2013-07-30
影响因子：
11.1
通讯作者：
Klionsky, Daniel J.
中科院分区：
文献类型：
--
作者：
Mao, Kai;Chew, Leon H.;Klionsky, Daniel J.
巨自噬（以下称为自噬）在细胞质的非选择性清除中起作用。这个过程参与细胞生理学的许多方面，并且在所有真核生物中是保守的。自噬开始于吞噬细胞组装位点（PAS）的组织，其中大多数自噬相关（Atg）蛋白至少是瞬时定位的。自噬发生在基础水平，可以由各种类型的应激诱导;该过程必须严格调节，因为自噬不足或过度可能是有害的。由Atg 17-Atg 31-Atg 29组成的复合物对PAS组织和自噬诱导至关重要，暗示在自噬调节中起重要作用。在这项研究中，我们证明，Atg 29是一个磷酸化的蛋白质，这种修改是至关重要的，它的功能;丙氨酸取代在磷酸化位点阻断其与支架蛋白Atg 11和它的能力，以促进组装的PAS的相互作用。Atg 29具有内在无序蛋白质的特征，表明其在与结合伴侣相互作用时经历动态构象变化。最后，单粒子电子显微镜分析的Atg 17-Atg 31-Atg 29复合物揭示了一个细长的结构与Atg 29位于相对的两端。
Macroautophagy (hereafter autophagy) functions in the nonselective clearance of cytoplasm. This process participates in many aspects of cell physiology, and is conserved in all eukaryotes. Autophagy begins with the organization of the phagophore assembly site (PAS), where most of the AuTophaGy-related (Atg) proteins are at least transiently localized. Autophagy occurs at a basal level and can be induced by various types of stress; the process must be tightly regulated because insufficient or excessive autophagy can be deleterious. A complex composed of Atg17-Atg31-Atg29 is vital for PAS organization and autophagy induction, implying a significant role in autophagy regulation. In this study, we demonstrate that Atg29 is a phosphorylated protein and that this modification is critical to its function; alanine substitution at the phosphorylation sites blocks its interaction with the scaffold protein Atg11 and its ability to facilitate assembly of the PAS. Atg29 has the characteristics of an intrinsically disordered protein, suggesting that it undergoes dynamic conformational changes on interaction with a binding partner(s). Finally, single-particle electron microscopy analysis of the Atg17-Atg31-Atg29 complex reveals an elongated structure with Atg29 located at the opposing ends.