Cirillo D M, Gaudino G, Naldini L, Comoglio P M
Mol Cell Biol. 1986 Dec;6(12):4641-9. doi: 10.1128/mcb.6.12.4641-4649.1986.
The neuropeptide bombesin is known for its potent mitogenic activity on murine 3T3 fibroblasts and other cells. Recently it has been implicated in the pathogenesis of small cell lung carcinoma, in which it acts through an autocrine loop of growth stimulation. Phosphotyrosine (P-Tyr) antibodies have been successfully used to recognize the autophosphorylated receptors for known growth factors. In Swiss 3T3 fibroblasts, phosphotyrosine antibodies identified a 115,000-Mr cell surface protein (p115) that became phosphorylated on tyrosine as a specific response to bombesin stimulation of quiescent cells. The extent of phosphorylation was dose dependent and correlated with the mitogenic effect induced by bombesin, measured by [3H]thymidine incorporation. Tyrosine phosphorylation of p115 was detectable minutes after the addition of bombesin, and its time course paralleled that described for the binding of bombesin to its receptor. Immunocomplexes of phosphorylated p115 and phosphotyrosine antibodies bound 125I-labeled [Tyr4]bombesin in a specific and saturable manner and displayed an associated tyrosine kinase activity enhanced by bombesin. Furthermore, the 125I-labeled bombesin analog gastrin-releasing peptide, bound to intact live cells, was coprecipitated with p115. These data strongly suggest that p115 participates in the structure and function of the surface receptor for bombesin, a new member of the family of growth factor receptors with associated tyrosine kinase activity.
神经肽蛙皮素以其对鼠3T3成纤维细胞和其他细胞的强大促有丝分裂活性而闻名。最近，它被认为与小细胞肺癌的发病机制有关，在小细胞肺癌中，它通过生长刺激的自分泌环发挥作用。磷酸酪氨酸（P-Tyr）抗体已成功用于识别已知生长因子的自磷酸化受体。在瑞士3T3成纤维细胞中，磷酸酪氨酸抗体鉴定出一种115,000道尔顿的细胞表面蛋白（p115），该蛋白在酪氨酸上磷酸化，作为对静止细胞蛙皮素刺激的特异性反应。磷酸化程度呈剂量依赖性，并且与通过[3H]胸苷掺入测量的蛙皮素诱导的促有丝分裂作用相关。在添加蛙皮素后几分钟即可检测到p115的酪氨酸磷酸化，其时间进程与蛙皮素与其受体结合的情况相似。磷酸化的p115和磷酸酪氨酸抗体的免疫复合物以特异性和可饱和的方式结合125I标记的[酪氨酸4]蛙皮素，并显示出由蛙皮素增强的相关酪氨酸激酶活性。此外，与完整活细胞结合的125I标记的蛙皮素类似物胃泌素释放肽与p115共沉淀。这些数据强烈表明，p115参与蛙皮素表面受体的结构和功能，蛙皮素是具有相关酪氨酸激酶活性的生长因子受体家族的新成员。
