Identification of two C‐terminal autophosphorylation sites in the PDGF beta‐receptor: involvement in the interaction with phospholipase C‐gamma.
Identification of two C‐terminal autophosphorylation sites in the PDGF beta‐receptor: involvement in the interaction with phospholipase C‐gamma.
复制标题
PDGF β 受体中两个 C 端自磷酸化位点的鉴定：参与与磷脂酶 C-γ 的相互作用。
作者：
L. Rönnstrand;S. Mori;A. Arridsson;A. Eriksson;C. Wernstedt;U. Hellman;L. Claesson;C. Heldin
两个新的自磷酸化位点位于血小板衍化生长因子β受体的C末端尾部。为了评估这些磷酸化位点的重要性，在猪主动脉内皮（PAE）细胞中表达受体突变体，其中Tyr 1009，Tyr 1021或两者都被苯丙氨酸残基取代。这些突变体在蛋白酪氨酸激酶活性和响应于PDGF-BB诱导促有丝分裂的能力方面与野生型受体相似。然而，与野生型PDGF β受体相比，Y1009 F和Y1021 F突变体介导磷脂酶C-γ（PLC-γ）的缔合和酪氨酸磷酸化的能力降低;在Y1009 F/Y1021 F双突变体的情况下，未检测到PLC-γ的缔合或磷酸化。这些数据表明，PLC-γ的酪氨酸磷酸化依赖于PDGF β受体Tyr 1009和Tyr 1021的自磷酸化。
Two novel sites of autophosphorylation were localized to the C‐terminal tail of the PDGF beta‐receptor. To evaluate the importance of these phosphorylation sites, receptor mutants in which Tyr1009, Tyr1021 or both were replaced with phenylalanine residues, were expressed in porcine aortic endothelial (PAE) cells. These mutants were similar to the wild type receptor with regard to protein tyrosine kinase activity and ability to induce mitogenicity in response to PDGF‐BB. However, both the Y1009F and Y1021F mutants showed a decreased ability to mediate association with and the tyrosine phosphorylation of phospholipase C‐gamma (PLC‐gamma) compared to the wild type PDGF beta‐receptor; in the case of the Y1009F/Y1021F double mutant, no association or phosphorylation of PLC‐gamma could be detected. These data show that tyrosine phosphorylation of PLC‐gamma is dependent on autophosphorylation of the PDGF beta‐receptor at Tyr1009 and Tyr1021.