PI4KIIα调控CD36从高尔基体往质膜转运的机制

棕榈酰化修饰能够作为一种分选信号介导蛋白质在细胞内的转运，但其机制不清。我们前期工作发现棕榈酰化修饰对清道夫受体CD36从高尔基体往质膜的分选及其脂肪酸吸收活性是必需的。本课题预实验过程中，我们以CD36为模式蛋白研究了棕榈酰化介导蛋白质从高尔基体往质膜转运的机制，发现磷脂酰肌醇4-激酶（PI4KIIα）在这个过程中扮演着重要的角色。为了进一步研究PI4KIIα的作用及分子机制，我们将从以下三个方面展开研究：1) 借助RUSH系统等明确PI4KIIα在CD36分选中的作用；2）借助突变和相互作用技术等明确PI4KIIα识别CD36的分子基础，分离并鉴定CD36分选过程中识别PI4P的蛋白，解析PI4KIIα在CD36分选中的分子机制；3）结合SILAC等方法揭示PI4KIIα在分选棕榈酰化修饰蛋白中的普适性。本项目有望揭示棕榈酰化修饰介导蛋白质分选的新机制。

Protein S-palmitoylation is a post-translational modification in eukaryotic proteins and it is the covalent attachment of the palmitoyl group to the thiol group of a Cys residue. It functions as a sorting signal to direct proteins to their destinations; however, the underlying mechanism is 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. In the preliminary studies of this project, we use CD36 as a model protein to study the sorting mechanism of palmitoylated proteins from Golgi to plasma membrane. We find that PI4KIIα plays a key role in this process. To further dissect the role of PI4KIIα, we will perform the following experiments: 1) Confirm the roles of PI4KIIα in the sorting of CD36 by the RUSH system; 2) Elucidate how PI4KIIα recognizes CD36 using techniques like site-directed mutagenesis and protein interaction. Identify the protein that recognize PI4P and uncover the underlying mechanism of how PI4KIIα facilitates the sorting of CD36; 3) Explore whether PI4KIIα plays a general role in sorting palmitoylated proteins from Golgi to the plasma membrane using SILAC. Our study will help to identify the mechanism of palmitoylation-based protein sorting, and shed insights into intracellular trafficking of proteins with lipid modifications.