昆虫必须从食物中获取固醇类化合物，并在中肠内将其转化为胆固醇以满足自身生长和繁殖所需，固醇转运蛋白2（HaSCP-2）在昆虫细胞吸收和转运胆固醇过程中发挥重要作用，是潜在的杀虫剂靶标。申请者以棉铃虫为研究材料，发现actin和ADF参与HaSCP-2在细胞内的转运调控，但具体机制尚不清楚。本研究拟在前期研究基础上，通过分子生物学技术表达和纯化actin及ADF蛋白；利用免疫共沉淀、等温热滴定等方法来测定actin/ADF蛋白与HaSCP-2的结合能力；然后使用计算机模拟分析、蛋白突变检测技术弄清actin/ADF蛋白与HaSCP-2的结合位点；最后基于荧光探针来测定分析actin/ADF对HaSCP-2的调控作用。本项目的实施旨在阐明actin/ADF与HaSCP-2相互作用的分子机制，为基于actin/ADF调控模式设计和开发HaSCP-2抑制剂提供依据。

Steroids from dietary sources must be obtained and transformed into cholesterol in midgut to meet the growth and reproduction required of insects. Sterol carrier protein-2 (SCP-2) has been shown to aid in the uptake and transport of cholesterol in insect’s cells; consequently, SCP-2 is a potential pesticide target. Using the Helicoverpa armigera as the research material, applicant has found that actin and ADF are involved in transport regulation of HaSCP-2, however, the exact mechanism is not clear. Based on the previous research, this study will express and purify the actin and ADF protein by molecular biology technology, and using the immune co-precipitation and isothermal titration calorimetric techniques to detect the binding activity of actin/ADF, then utilizing the computer-based simulation and biochemical technology to determine the binding sites, finally analyzing the regulation mechanism of actin/ADF with fluorescence probe. This study is intended to clarify the molecular mechanism of interaction between actin/ADF and HaSCP-2, and provide foundation for designing and developing inhibitors of HaSCP-2 based on the actin/ADF regulation patterns.