Hamaguchi M, Hanafusa H
Rockefeller University, New York, New York 10021.
Oncogene Res. 1989;4(1):29-37.
Subcellular localization of potential substrates of a tyrosine-protein kinase, p60v-src, was analyzed by cell fractionation in combination with immunoblotting with antiphosphotyrosine antibody. In cells transformed by wild type Rous sarcoma virus, most phosphotyrosine-containing proteins were found both in plasma membranes and in a cytoplasmic matrix structure associated with plasma membranes and resistant to nonionic detergent extraction (plasma membrane matrix). A similar localization of phosphotyrosine-containing proteins was obtained in cells transformed by PRCII, Y73, or Fujinami sarcoma virus. On the other hand, in cells infected with Rous sarcoma virus mutants that encode nonmyristylated p60v-src, tyrosine phosphorylation was found mostly in proteins which were different from those identified in wild type-infected cells and were distributed to both plasma membrane and cytosolic fractions. These results suggest that most cellular substrate proteins, phosphorylation of some of which may be critical for the initiation of transformation, are present primarily in the plasma membrane-matrix structure.
通过细胞分级分离结合抗磷酸酪氨酸抗体免疫印迹法，分析了酪氨酸蛋白激酶p60v-src潜在底物的亚细胞定位。在野生型劳氏肉瘤病毒转化的细胞中，大多数含磷酸酪氨酸的蛋白质存在于质膜以及与质膜相关且对非离子去污剂提取有抗性的细胞质基质结构（质膜基质）中。在用PRCII、Y73或 Fujinami肉瘤病毒转化的细胞中，也获得了含磷酸酪氨酸蛋白质的类似定位。另一方面，在感染了编码非肉豆蔻酰化p60v-src的劳氏肉瘤病毒突变体的细胞中，酪氨酸磷酸化主要存在于与野生型感染细胞中鉴定出的蛋白质不同的蛋白质中，这些蛋白质分布在质膜和胞质组分中。这些结果表明，大多数细胞底物蛋白主要存在于质膜-基质结构中，其中一些蛋白的磷酸化可能对转化的起始至关重要。
