Phosphoinositides are membrane lipids generated by phosphorylation on the inositol head group of phosphatidylinositol. By specifically distributed to distinct subcellular membrane locations, different phosphoinositide species play diverse roles in modulating membrane trafficking. Among the seven known phosphoinositide species, phosphatidylinositol 4,5-bisphosphate (PI4,5P₂) is the one species most abundant at the plasma membrane. Thus, the PI4,5P₂ function in membrane trafficking is first identified in controlling plasma membrane dynamic-related events including endocytosis and exocytosis. However, recent studies indicate that PI4,5P₂ is also critical in many other membrane trafficking events such as endosomal trafficking, hydrolases sorting to lysosomes, autophagy initiation, and autophagic lysosome reformation. These findings suggest that the role of PI4,5P₂ in membrane trafficking is far beyond just plasma membrane. This review will provide a concise synopsis of how PI4,5P₂ functions in multiple membrane trafficking events. PI4,5P₂, the enzymes responsible for PI4,5P₂ production at specific subcellular locations, and distinct PI4,5P₂ effector proteins compose a regulation network to control the specific membrane trafficking events.

中文翻译：

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磷脂酰肌醇 4,5-二磷酸酯在控制膜贩运中的作用

磷脂酰肌醇是由磷脂酰肌醇的肌醇头基磷酸化产生的膜脂。通过特异性分布到不同的亚细胞膜位置，不同的磷酸肌醇种类在调节膜运输中发挥不同的作用。在七种已知的磷酸肌醇种类中，4,5-二磷酸磷脂酰肌醇 (PI4,5P ₂ ) 是质膜上最丰富的一种。因此，膜运输中的 PI4,5P ₂功能首先在控制质膜动态相关事件中被确定，包括内吞作用和胞吐作用。然而，最近的研究表明 PI4,5P ₂在许多其他膜运输事件中也很关键，例如内体运输、水解酶分选成溶酶体、自噬启动和自噬溶酶体重组。这些发现表明，PI4,5P ₂在膜运输中的作用远远超出了质膜。这篇综述将简要概述 PI4,5P ₂如何在多个膜运输事件中发挥作用。PI4,5P ₂是负责在特定亚细胞位置产生 PI4,5P 2 的酶_，以及不同的 PI4,5P ₂效应蛋白组成一个调节网络来控制特定的膜运输事件。