Pallas D C, Cherington V, Morgan W, DeAnda J, Kaplan D, Schaffhausen B, Roberts T M
Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
J Virol. 1988 Nov;62(11):3934-40. doi: 10.1128/JVI.62.11.3934-3940.1988.
We have used two-dimensional gel electrophoresis to analyze in more detail the cellular proteins which associate with the middle and small tumor antigens (MT and ST, respectively) of polyomavirus. Proteins with molecular masses of 27, 29, 36, 51, 61, 63, and 85 kilodaltons (kDa) that specifically coimmunoprecipitated with MT were identified on these gels. The 36-, 51-, 61-, 63-, and 85-kDa proteins are probably the same as the proteins of similar sizes previously reported by a number of groups, whereas the 27- and 29-kDa proteins represent proteins that are heretofore undescribed. The 27- and 29-kDa proteins were abundant cellular proteins, whereas the others were minor cellular constituents. The association of each of these proteins with MT was sensitive to one or more mutations in MT that rendered it transformation defective. The association of the 85-kDa protein was the most sensitive indicator of the transformation competence of MT mutants. In addition, the 85-kDa protein was the only associated protein whose association with MT changed consistently in parallel with MT-associated phosphatidylinositol kinase activity. Furthermore, the fraction of the 85-kDa protein which was found associated with the MT complex contained 15 to 20% of its phosphate content on tyrosine. The 36- and 63-kDa proteins complexed with both polyomavirus MT and ST and comigrated on two-dimensional gels with two simian virus 40 ST-associated proteins originally described by Rundell and coworkers (K. Rundell, E. O. Major, and M. Lampert, J. Virol. 37:1090-1093, 1981). None of the other MT-associated proteins associated significantly with ST.
我们运用二维凝胶电泳更详细地分析了与多瘤病毒的中、小肿瘤抗原（分别为MT和ST）相关的细胞蛋白。在这些凝胶上鉴定出了分子量分别为27、29、36、51、61、63和85千道尔顿（kDa）的蛋白，它们能与MT特异性共免疫沉淀。36、51、61、63和85 kDa的蛋白可能与先前多个研究小组报道的大小相似的蛋白相同，而27和29 kDa的蛋白代表此前未描述过的蛋白。27和29 kDa的蛋白是丰富的细胞蛋白，而其他蛋白是次要的细胞成分。这些蛋白中的每一种与MT的结合对MT中一个或多个使其转化缺陷的突变敏感。85 kDa蛋白的结合是MT突变体转化能力最敏感的指标。此外，85 kDa蛋白是唯一一种与MT的结合随MT相关磷脂酰肌醇激酶活性平行一致变化的相关蛋白。此外，在与MT复合物结合的85 kDa蛋白部分中，其酪氨酸上的磷酸含量占15%至20%。36和63 kDa的蛋白与多瘤病毒MT和ST都形成复合物，并且在二维凝胶上与最初由Rundell及其同事描述的两种猴病毒40 ST相关蛋白（K. Rundell、E. O. Major和M. Lampert，《病毒学杂志》37:1090 - 1093，1981）迁移情况相同。其他与MT相关的蛋白均未与ST显著结合。
