Westermark B, Siegbahn A, Heldin C H, Claesson-Welsh L
Department of Pathology, University of Uppsala, Sweden.
Proc Natl Acad Sci U S A. 1990 Jan;87(1):128-32. doi: 10.1073/pnas.87.1.128.
Porcine aorta endothelial cells are devoid of receptors for platelet-derived growth factor (PDGF). We have transfected such cells with cDNA for the PDGF B-type receptor, both the wild-type receptor and a mutant form of the receptor (K634A), in which the putative nucleotide-binding lysine of the protein-tyrosine domain has been changed to alanine. Immunoprecipitation studies of metabolically labeled cells showed that both types of receptors were synthesized and processed to the mature form of Mr 190,000. In cells expressing the wild-type receptor, PDGF-BB, the natural ligand for the B-type receptor, induced membrane ruffling and reorganization of actin. Such a response has previously been seen in cells expressing the natural PDGF B-type receptor in response to PDGF-BB. No such effect was induced in nontransfected cells or in cells expressing the K634A mutant receptor. PDGF was also shown to be chemotactic for cells expressing the wild-type receptor, whereas no chemotactic response was elicited in control cells or in cells expressing the K634A mutant receptor. Our study thus provides formal evidence that the PDGF B-type receptor mediates a motility response including actin reorganization and chemotaxis. Furthermore, the results establish a role for the receptor-associated protein-tyrosine kinase in the transduction of the chemotactic signal.
猪主动脉内皮细胞缺乏血小板衍生生长因子（PDGF）的受体。我们用PDGF B型受体的cDNA转染了这类细胞，该受体既有野生型，也有突变型（K634A），其中蛋白酪氨酸结构域中假定的核苷酸结合赖氨酸已被替换为丙氨酸。对代谢标记细胞的免疫沉淀研究表明，这两种受体均被合成并加工成分子量为190,000的成熟形式。在表达野生型受体的细胞中，B型受体的天然配体PDGF-BB可诱导膜皱褶和肌动蛋白重排。此前在表达天然PDGF B型受体的细胞中，对PDGF-BB也曾观察到这种反应。在未转染的细胞或表达K634A突变受体的细胞中未诱导出这种效应。PDGF对表达野生型受体的细胞也具有趋化作用，而在对照细胞或表达K634A突变受体的细胞中未引发趋化反应。因此，我们的研究提供了正式证据，证明PDGF B型受体介导包括肌动蛋白重排和趋化作用在内的运动反应。此外，结果确立了受体相关蛋白酪氨酸激酶在趋化信号转导中的作用。
