Derman M P, Chen J Y, Spokes K C, Songyang Z, Cantley L G
Division of Nephrology, Beth Israel Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.
J Biol Chem. 1996 Feb 23;271(8):4251-5. doi: 10.1074/jbc.271.8.4251.
Interaction of hepatocyte growth factor with its high affinity receptor c-met initiates a cascade of intracellular events leading to epithelial motility. An 11-amino acid sequence from the c-met receptor has been found to cause cell transformation in transfected fibroblasts (Ponzetto, C., Bardelli, A., Zhen, Z., Maina, F., Dalla, Z. P., Giordano, S., Graziani, A., Panayotou, G., and Comoglio, P. M.(1994) Cell 77, 261-271). We inserted this sequence into a mutant platelet-derived growth factor receptor (F5) to determine if this region of c-met can initiate cell motility and which signaling pathways it activates. The platelet-derived growth factor (PDGF) receptor/c-met hybrid (F5 met) initiated PDGF-dependent chemotaxis in renal epithelial cells (8.0 +/- 2.3 versus 70.5 +/- 4.8 cells/mm2), while the parental construct, F5, did not. Addition of PDGF to cells expressing F5 met caused activation of the phosphatidylinositol (PI) 3-kinase (control 2.0 +/- 0.8, +PDGF 17.1 +/- 5.1, n = 3, p < 0.05) and phospholipase C (control 478.5 +/- 67 dpm/well, +PDGF 1049.3 +/- 93, n = 4, p = 0.003), while neither pathway was activated in cells expressing F5. The chemotactic response of F5 met was inhibited by both the PI 3-kinase inhibitor wortmannin and the phospholipase C inhibitor U-71322. Selective activation of the PI 3-kinase utilizing a PDGF receptor mutant (F3) containing the native high affinity PI 3-kinase binding site also resulted in PDGF stimulated chemotaxis, although less than that generated by the c-met sequence. These findings demonstrate that the 11-amino acid sequence from c-met initiates epithelial motility via coincident activation of the PI 3-kinase and phospholipase C and that selective activation of the PI 3-kinase can initiate a partial chemotactic response.
肝细胞生长因子与其高亲和力受体c-met相互作用，引发一系列细胞内事件，导致上皮细胞迁移。已发现c-met受体的一段11个氨基酸的序列可使转染的成纤维细胞发生细胞转化（庞泽托，C.，巴尔德利，A.，甄，Z.，马伊纳，F.，达拉，Z.P.，乔达诺，S.，格拉齐亚尼，A.，帕纳约托，G.，和科莫利奥，P.M.（1994年）《细胞》77卷，261 - 271页）。我们将此序列插入突变型血小板衍生生长因子受体（F5）中，以确定c-met的这一区域是否能引发细胞迁移以及它激活了哪些信号通路。血小板衍生生长因子（PDGF）受体/c-met杂交体（F5 met）在肾上皮细胞中引发了依赖PDGF的趋化作用（8.0±2.3对70.5±4.8个细胞/mm²），而亲本构建体F5则没有。向表达F5 met的细胞中添加PDGF导致磷脂酰肌醇（PI）3激酶激活（对照组2.0±0.8，+PDGF组17.1±5.1，n = 3，p < 0.05）和磷脂酶C激活（对照组478.5±67 dpm/孔，+PDGF组1049.3±93，n = 4，p = 0.003），而在表达F5的细胞中这两条通路均未被激活。F5 met的趋化反应受到PI 3激酶抑制剂渥曼青霉素和磷脂酶C抑制剂U - 71322的抑制。利用含有天然高亲和力PI 3激酶结合位点的PDGF受体突变体（F3）选择性激活PI 3激酶也导致了PDGF刺激的趋化作用，尽管比c-met序列产生的趋化作用要小。这些发现表明，c-met的11个氨基酸序列通过同时激活PI 3激酶和磷脂酶C引发上皮细胞迁移，并且PI 3激酶的选择性激活可引发部分趋化反应。
