Site-selective dephosphorylation of the platelet-derived growth factor β-receptor by the receptor-like protein-tyrosine phosphatase DEP-1
Site-selective dephosphorylation of the platelet-derived growth factor β-receptor by the receptor-like protein-tyrosine phosphatase DEP-1
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DOI：
10.1074/jbc.275.21.16219
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发表时间：
2000-05-26
影响因子：
4.8
通讯作者：
Östman, A
中科院分区：
文献类型：
--
作者：
Kovalenko, M;Denner, K;Östman, A
配体刺激PDGF p受体可导致调节性酪氨酸857和酪氨酸残基的自磷酸化，酪氨酸残基磷酸化后可作为Src同源2结构域蛋白的对接位点。蛋白酪氨酸磷酸酶对PDGF β受体的调控尚不清楚。我们研究了受体样蛋白酪氨酸磷酸酶DEP-1对PDGF β受体的去磷酸化作用，使用可诱导DEP-1表达的细胞系，并表征了DEP-1对PDGF β受体和受体衍生的磷酸肽的体外去磷酸化作用。DEP-1诱导后，观察到PDGF β受体DEP-1复合物和受体酪氨酸磷酸化减少。对来自表达DEP-1细胞的PDGF p受体和体外被DEP-1去磷酸化的受体的磷酸化肽分析表明，受体自磷酸化位点的去磷酸化不同，并揭示了调节性Tyr(p)（857）不是DEP-1去磷酸化的首选位点。当分析合成受体衍生肽的去磷酸化时，选择性重现。表明磷酸化位点周围的氨基酸序列是选择性的主要决定因素。这一观点得到了观察结果的支持，即与其他分析的磷酸化位点相比，去磷酸化程度较低的Tyr(P)（562）和Tyr(P)（857）被相对于酪氨酸残基的-4和+3位置的碱性氨基酸残基包围。我们的研究表明，PDGF β受体的DEP-1去磷酸化是位点选择性的，可能导致信号的调节，而不是一般的衰减。
Ligand stimulation of PDGF P-receptors leads to autophosphorylation of the regulatory tyrosine 857 and of tyrosine residues that in their phosphorylated form serve as docking sites for Src homology 2 domain-containing proteins. Regulation of the PDGF beta-receptor by protein-tyrosine phosphatases is poorly understood. We have investigated PDGF beta-receptor dephosphorylation by receptor-like protein-tyrosine phosphatase DEP-1 using a cell line with inducible DEP-1 expression and by characterizing in vitro dephosphorylation of the PDGF beta-receptor and of receptor-derived phosphopeptides by DEP-1. After DEP-1 induction PDGF beta-receptor DEP-1 complexes and reduced receptor tyrosine phosphorylation were observed. Phosphopeptide analysis of the PDGF P-receptors from DEP-1-expressing cells and of the receptors dephosphorylated in vitro by DEP-1 demonstrated that dephosphorylation of autophosphorylation sites of the receptor differed and revealed that the regulatory Tyr(p)(857) was not a preferred site for DEP-1 dephosphorylation, When dephosphorylation of synthetic receptor-derived peptides was analyzed, the selectivity was reproduced, indicating that amino acid sequence surrounding the phosphorylation sites is the major determinant of selectivity. This notion is supported by the observation that the poorly dephosphorylated Tyr(P)(562) and Tyr(P)(857), in contrast to other analyzed phosphorylation sites, are surrounded by basic amino acid residues at positions -4 and +3 relative to the tyrosine residue. Our study demonstrates that DEP-1 dephosphorylation of the PDGF beta-receptor is site-selective and may lead to modulation, rather than general attenuation, of signaling.