Santos M, Butel J S
J Cell Biochem. 1982;19(2):127-44. doi: 10.1002/jcb.240190204.
The possible interaction between simian virus 40 (SV40) large tumor antigen (T-ag) and cellular proteins in the plasma membrane of SV40-transformed mouse cells was investigated. The presence of SV40 T-ag, 53,000 (53K) cellular protein, and histocompatibility (H-2) antigens on the surface of SV40-transformed cells was demonstrated by immunofluorescence. The use of lactoperoxidase-catalyzed cell surface iodination and a differential immunoprecipitation technique established that large T-ag is associated with the 53K host-coded protein on the surface of the transformed cells. In contrast, no detergent-stable complex between large t-ag and H-2 antigens was detected. Both labeled T-ag and 53K protein were coprecipitated from surface-iodinated SV40-transformed cells by monoclonal antibodies directed against either the viral or the cellular protein. Based on the unique antigenic sites recognized by the anti-T monoclonal antibodies, it appears that both the carboxy and amino termini of the T-ag polypeptide are exposed on the surface of SV40-transformed mouse cells. The nature of the association between surface T-ag and 53K protein, as well as that between the molecular complex and the plasma membrane, remains to be determined. The possible effect of the surface-associated T-ag/53K complex on cellular proliferation is considered.
研究了猿猴病毒40（SV40）大T抗原（T-ag）与SV40转化的小鼠细胞质膜中细胞蛋白之间可能存在的相互作用。通过免疫荧光证明了SV40转化细胞表面存在SV40 T-ag、53000（53K）细胞蛋白和组织相容性（H-2）抗原。利用乳过氧化物酶催化的细胞表面碘化和差异免疫沉淀技术确定，大T-ag与转化细胞表面的53K宿主编码蛋白相关。相比之下，未检测到大T-ag与H-2抗原之间存在去污剂稳定复合物。针对病毒或细胞蛋白的单克隆抗体从表面碘化的SV40转化细胞中共沉淀出标记的T-ag和53K蛋白。基于抗T单克隆抗体识别的独特抗原位点，似乎T-ag多肽的羧基和氨基末端都暴露在SV40转化的小鼠细胞表面。表面T-ag与53K蛋白之间的关联性质，以及分子复合物与质膜之间的关联性质，仍有待确定。考虑了表面相关的T-ag/53K复合物对细胞增殖的可能影响。
