Nephrin是定位于足细胞裂隙膜的重要结构蛋白和信号转导分子，其磷酸化改变在调节足细胞存活及骨架蛋白重组中起重要作用，但nephrin磷酸化调控机制仍不清楚。Fyn激酶是磷酸化nephrin胞内段的关键激酶，C末端Src激酶（Csk）是 Fyn的特异性负性调控因子。本项目拟探讨Csk在足细胞正常及损伤状态下参与调控nephrin磷酸化改变的作用及分子机制。通过血管紧张素Ⅱ输注大鼠模型及培养足细胞，评价nephrin磷酸化及足细胞损伤，观察Csk在足细胞表达、分布及与caveolin-1、Fyn蛋白间相互作用特点；通过siRNA下调足细胞Csk表达和在HEK293T细胞共转染Csk突变质粒/Fyn C末端Try530突变质粒和nephrin表达质粒，分析Csk调控nephrin磷酸化改变的分子机制，明确Csk在调控足细胞nephrin磷酸化中的作用，为有效防治足细胞损伤提供新的理论依据。

Nephrin is an important structural and signal transduction molecule located in slit diaphragm of podocyte.The change of nephrin phosphorylation contributes to the survival and cytoskeleton reorganization of podocyte. But, the mechanism of nephrin phosphorylation regulation is still unclear. Fyn is the key kinase that phosphorylates nephrin intracellular domain. C-terminal Src kinase (Csk) is specific negative regulatory factor of Fyn. This project proposed to further explore the role and molecular mechanisms of Csk involved in the regulation of nephrin phosphorylation in normal or injury podocyte state. By angiotensin II stimulation of cultured podocytes, we will evaluate the impact of angiotensin II on the nephrin phosphorylation and podocyte injury, and observe the expression and distribution of Csk and the interactions with caveolin-1 and Fyn. Through the down-regulation of Csk by siRNA, and co-transfection with Csk mutant plasmids/Fyn C terminal Try 530 mutant plasmids and nephrin plasmids, we will analyze the characteristics of nephrin phosphorylation regulated by Csk, and further confirm the role of Csk in the regulation of nephrin phosphorylation, and provide a new theoretical basis for the effective prevention of podocyte injury.