Sato T A, Kohama T, Sugiura A
Department of Measles Virus, National Institute of Health, Tokyo, Japan.
Arch Virol. 1988;98(1-2):39-50. doi: 10.1007/BF01321004.
Intracellular processing of measles virus fusion (F) protein was studied by radiolabeling and immunoprecipitation with a monoclonal antibody against F protein. The cleavage of F protein into F1 and F2 subunits was complete after 5 hours of chase during which the growth of oligosaccharide chains on the F2 domain of F protein continued. The addition of terminal sialic acid conferred a strong negative charge on the F2 subunit. F protein expressed on the cell surface was removed by a fungal semi-alkaline protease, providing a method to follow the kinetics of its transport to the cell surface. The transport of the F protein was faster than that of the hemagglutinin (HA) protein. Uncleaved F protein, as well as cleaved subunits became digestible by the protease, indicating that a portion of the F protein reaches the cell surface uncleaved. The treatment of measles virus-infected cells with tunicamycin resulted in the synthesis of unglycosylated HA (65 kilodaltons, Kd) and F (48 Kd) proteins. Unglycosylated F protein was not cleaved into smaller subunits, nor was it transported to the cell surface. Unglycosylated HA protein likewise failed to reach the cell surface.
通过放射性标记和使用抗F蛋白单克隆抗体进行免疫沉淀，研究了麻疹病毒融合（F）蛋白的细胞内加工过程。在5小时的追踪期后，F蛋白裂解为F1和F2亚基的过程完成，在此期间F蛋白F2结构域上的寡糖链继续生长。末端唾液酸的添加赋予F2亚基很强的负电荷。细胞表面表达的F蛋白可被真菌半碱性蛋白酶去除，这提供了一种追踪其转运至细胞表面动力学的方法。F蛋白的转运速度比血凝素（HA）蛋白快。未裂解的F蛋白以及裂解后的亚基都可被蛋白酶消化，这表明一部分F蛋白未裂解就到达了细胞表面。用衣霉素处理麻疹病毒感染的细胞，导致未糖基化的HA（65千道尔顿，Kd）和F（48 Kd）蛋白的合成。未糖基化的F蛋白未裂解为更小的亚基，也未转运至细胞表面。同样，未糖基化的HA蛋白也未能到达细胞表面。
