Role of the p97 ATPase in endocytosis

p97 ATP 酶在内吞作用中的作用

• 批准号: 8553639
• 负责人: Yihong Ye
• 金额: $ 27.16万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8553639
• 关键词: ATP phosphohydrolase; Autoantigens; Binding; Biochemical; C2H2 Zinc Finger; Cell physiology; Cells; Complex; Early Endosome; Endocytosis; Endoplasmic Reticulum; Goals; Membrane; Membrane Fusion; Modification; Mono-S; N-ethylmaleimide-sensitive protein; N-terminal; Pattern; Proteins; Role; SNAP receptor; Small Interfering RNA; Ubiquitination; Zinc Fingers; endosome membrane; inhibitor/antagonist; multicatalytic endopeptidase complex; novel; p97 ATPase; protein misfolding; trafficking

The AAA (ATPase-associated with various cellular activities) ATPase p97 acts on diverse substrate proteins to partake in various cellular processes such as membrane fusion and endoplasmic reticulum-associated degradation (ERAD). In membrane fusion, p97 is thought to function in analogy to the related ATPase NSF (N-ethylmaleimide sensitive fusion protein), which promotes membrane fusion by disassembling a SNARE complex. In ERAD, p97 dislocates misfolded proteins from the ER membrane to facilitate their turnover by the proteasome. Here, we identify a novel function of p97 in endocytic trafficking by establishing the early endosomal autoantigen 1 (EEA1) as a new p97 substrate. We demonstrate that a fraction of p97 is localized to the early endosome membrane, where it binds EEA1 via the N-terminal C2H2 zinc finger domain. Inhibition of p97 either by siRNA or a pharmacological inhibitor results in clustering and enlargement of early endosomes, which is associated with an altered trafficking pattern for an endocytic cargo. Mechanistically, we show that p97 inhibition causes increased EEA1 self-association at the endosome membrane. We propose that p97 may regulate the size of early endosomes by governing the oligomeric state of EEA1. We recently further demonstrate that EEA1 undergoes mono-ubiquitination in the cell and this modification can regulate the size of early endosomes.

ATPase p97作用于不同的底物蛋白，参与多种细胞过程，如膜融合和内质网相关降解。在膜融合中，p97的功能被认为类似于相关的ATPase NSF(N-乙基马来酰亚胺敏感融合蛋白)，后者通过分解SNARE复合体来促进膜融合。在ERAD中，p97使错误折叠的蛋白质从内质网膜上移位，以促进蛋白酶体的周转。在这里，我们通过建立早期内体自身抗原1(EEA1)作为新的p97底物来鉴定p97在内吞转运中的新功能。我们证明了p97的一部分定位于早期的内吞体膜，在那里它通过N端的C2H2锌指结构域与EEA1结合。用siRNA或药物抑制剂抑制p97会导致早期内小体聚集和增大，这与内吞货物运输模式的改变有关。从机制上讲，我们证明了p97抑制导致内吞体膜上EEA1自结合增加。我们认为p97可能通过调控EEA1的寡聚体状态来调节早期内体的大小。我们最近进一步证明了EEA1在细胞中经历了单一泛素化，这种修饰可以调节早期内小体的大小。

项目成果

Cellular strategies for making monoubiquitin signals.

• DOI: 10.3109/10409238.2011.620943
• 发表时间: 2012-01
• 期刊: Critical reviews in biochemistry and molecular biology
• 影响因子: 6.5
• 作者: Ramanathan HN;Ye Y
• 通讯作者: Ye Y