ARF6介导棕榈酰化CD36定向分选到细胞膜的机制研究

蛋白质棕榈酰化修饰是蛋白质脂酰化修饰的一种，在调控蛋白质的亚细胞器定位和分选具有重要的作用，但是棕榈酰化修饰蛋白质的分选机制目前并不清楚。我们前期工作发现清道夫受体CD36的棕榈酰化修饰对其从高尔基体往质膜的分选及脂肪酸吸收活性是必需的（Cell Reports， 2019），因此我们拟利用CD36作为模式蛋白研究棕榈酰化修饰蛋白的分选。我们前期筛选了在脂肪组织中表达较高的41个小G蛋白，发现RAB43和ARF6对于CD36的质膜定位是必需的，并进一步发现ARF6对于CD36从高尔基体往质膜的分选是必需的。我们将通过RUSH系统和串联亲和纯化等细胞和生化手段进一步明确ARF6在分选中的作用，鉴定辅助ARF6作用的其它蛋白，阐明ARF6作用的分子机制，并揭示ARF6在分选棕榈酰化修饰蛋白中的普适性。本研究有望揭示棕榈酰化修饰在蛋白质分选中的作用机制，并为脂酰化蛋白的分选提供理论指导。

Protein palmitoylation is a type of lipid modifications of proteins, and it provides a key mechanism in regulating the subcellular localization and intracellular tracking of proteins. However, how palmitoylated proteins are sorted to their target membranes remains unknown. We have previously shown that the palmitoylation of CD36, a scavenge receptor, is required for the intracellular sorting from Golgi to the plasma membrane and fatty acid uptake activity. We therefore plan to use CD36 as a model protein to study the sorting mechanism of palmitoylated proteins. We performed a shRNA screening targeting 41 of the abundant small GTPases in adipose tissues, and found that RAB43 and ARF6 were required for the plasma membrane localization of CD36. We further demonstrated that ARF6 played an essential role of sorting palmitoylated CD36 from Golgi to the plasma membrane. We plan to use tools like RUSH system and tandem purification to further confirm the roles of ARF6 in the sorting, identify the effectors proteins of ARF6 and uncover the underlying mechanism of ARF6-assisted sorting of palmitoylated CD36. We will also explore whether ARF6 plays a general role in sorting palmitoylated proteins from Golgi to the plasma membrane. Our study will help to identify the mechanism of palmitoylation-based protein sorting, and shed insights into intracellular trafficking of proteins with lipid modifications.