Pober J S, Guild B C, Strominger J L
Proc Natl Acad Sci U S A. 1978 Dec;75(12):6002-6. doi: 10.1073/pnas.75.12.6002.
HLA-A and -B antigens are phosphorylated in transformed lymphoblastoid cells and peripheral blood lymphocytes, both incubated with 32Pi. The phosphate group is attached to HLA-A and -B heavy chain (p44) as identified by immunoprecipitation with anti-beta2-microglobulin IgG, sodium dodecyl sulfate/polyacrylamide gel electrophoresis, isoelectric focusing, and susceptibility to limited proteolysis by papain and trypsin. The site(s) of phosphorylation is identified as a serine residue(s) located in the hydrophilic carboxy terminus of the p44 chain. HLA antigens are also phosphorylated in isolated membranes from transformed lymphoblastoid cells that are incubated with [gamma32P]ATP. The phosphorylation of the carboxy terminus of HLA-A and -B antigens in vivo is good evidence that this portion of the molecule is intracellular. Furthermore, this modification suggests a general way in which interactions between membrane proteins and cytoskeletal elements may be regulated.
在与³²Pi一起孵育的转化淋巴母细胞和外周血淋巴细胞中,HLA - A和 - B抗原发生了磷酸化。通过用抗β2 - 微球蛋白IgG进行免疫沉淀、十二烷基硫酸钠/聚丙烯酰胺凝胶电泳、等电聚焦以及木瓜蛋白酶和胰蛋白酶有限蛋白水解敏感性鉴定,磷酸基团附着在HLA - A和 - B重链(p44)上。磷酸化位点被确定为位于p44链亲水性羧基末端的一个或多个丝氨酸残基。在与[γ³²P]ATP一起孵育的转化淋巴母细胞的分离膜中,HLA抗原也发生了磷酸化。HLA - A和 - B抗原羧基末端在体内的磷酸化充分证明该分子的这一部分位于细胞内。此外,这种修饰提示了一种调节膜蛋白与细胞骨架成分之间相互作用的一般方式。