Winegar D A, Molina y Vedia L, Lapetina E G
Division of Cell Biology, Burroughs Wellcome Company, Research Triangle Park, North Carolina 27709.
J Biol Chem. 1991 Mar 5;266(7):4381-6.
The covalent modification of proteins by isoprenoid derivatives of mevalonic acid was investigated in human platelets, cells that lack the ability to synthesize endogenous cholesterol, and human erythroleukemia (HEL) cells, cholesterol-producing cultured cells derived from megakaryocytes. When washed platelets or HEL cells were incubated with [3H]mevalonic acid, the radiolabel was incorporated into a distinct group of proteins with molecular masses between 21,000 and 28,000. We have identified one of these proteins as a ras-related rap2 protein based on its immunoreactivity with a polyclonal antiserum raised against purified recombinant rap2b. This anti-rap2 antiserum was used for two-dimensional immunoblotting analysis and immunoprecipitation of mevalonate-labeled rap2 from platelets and HEL cells. These results suggest that rap2 may undergo a series of carboxyl-terminal modifications similar to the p21ras proteins. In addition, it is shown that non-cholesterol-producing cells are capable of incorporating isoprenyl groups into specific proteins.
在人类血小板（缺乏合成内源性胆固醇能力的细胞）和人红白血病（HEL）细胞（源自巨核细胞的产生胆固醇的培养细胞）中研究了甲羟戊酸的类异戊二烯衍生物对蛋白质的共价修饰。当洗涤后的血小板或HEL细胞与[3H]甲羟戊酸一起孵育时，放射性标记掺入到一组分子量在21,000至28,000之间的独特蛋白质中。基于其与针对纯化重组rap2b产生的多克隆抗血清的免疫反应性，我们已将其中一种蛋白质鉴定为与ras相关的rap2蛋白。该抗rap2抗血清用于二维免疫印迹分析以及从血小板和HEL细胞中免疫沉淀甲羟戊酸标记的rap2。这些结果表明rap2可能经历一系列类似于p21ras蛋白的羧基末端修饰。此外，研究表明非产生胆固醇的细胞能够将异戊烯基掺入特定蛋白质中。
