目的:分析前列腺癌基因17(PRC17)与人肌球蛋白调节轻链(MLC2)之间的相互作用,并鉴定PRC17蛋白序列上与MLC2相互作用的功能区域。方法:经大肠杆菌表达并用GlutathioneSepharose4B纯化GST及融合蛋白GST-MLC2,用SMMC-7721细胞表达带HA标签的PRC17及其截短突变体HA-PRC17(353)、HA-PRC17(251)、HA-PRC17(164)和HA-PRC17(A164),GST沉淀实验分析GsT-MLC2与PRCl7及其截短体的相互作用。结果:经诱导表达并纯化的GST和GST-MLC2分子质量符合预期,分别约为28.4kD和46.6kD,纯度均95%以上;GST沉淀实验结果显示,PRC17结合MLC2,不结合阴性对照GST;PRC17(353)和PRC17(251)也能有效结合MLC2,但PRC17(164)和PRC17(A164)都不能与MLC2结合。结论:PRC17能特异性结合MLC2,其蛋白序列上与MLC2结合的部位位于其氨基端251位氨基酸之内,可能在164位氨基酸附近。
Objective: To analyze the interaction between PRC17 and MLC2 and identify MLC2-binding site on PRC17. Methods: GST (glutathione-s-transferase) and GST-MLC2 fusion protein were expressed in E. coli BL21 and purified by Glutathione Sepharose 4B affinity chromatography. HA-tagged PRC17 and truncated PRC17 mutants HA- PRC17 ( 353 ), HA- PRC17 (251), HA- PRC17 ( 164 ) and HA- PRC17 ( A164 ) were expressed in SMMC-7721 ceils. The GST-pull down assay was performed to test the interaction of MLC2 with HA-PRC17 andPRC17 mutants respectively. Results: GST and GST-MLC2 were induced to be expressed in E. coli BL21, and their molecular weights were consistent to the anticipated molecular weights ,28.4 kD and 46. 6 kD respectively. The purity of both GST and GST-MLC2 was above 95% respectively; GST pull-down assay showed that PRC17 could bind to GST-MLC2, but could not bind to negative control GST protein;PRC17 (353)and PRC17 (251 )could bind to MLC2 as well, however, PRC17 (164) and PRC17 (A164) could not bind to MLC2. Conclusion: PRC17 could interact specifically with MLC2 within 251 aminos in N- terminal of PRC17,in particular around the 164th animo.