PLD2 Complexes with the EGF Receptor and Undergoes Tyrosine Phosphorylation at a Single Site upon Agonist Stimulation*
PLD2 Complexes with the EGF Receptor and Undergoes Tyrosine Phosphorylation at a Single Site upon Agonist Stimulation*
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DOI：
10.1074/jbc.273.50.33722
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发表时间：
1998-12
期刊：
影响因子：
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通讯作者：
R. Slaaby;T. Jensen;H. Hansen;M. Frohman;K. Seedorf
中科院分区：
文献类型：
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作者：
R. Slaaby;T. Jensen;H. Hansen;M. Frohman;K. Seedorf
当细胞受到多种激素、生长因子和其他细胞外信号刺激时，哺乳动物磷脂酶 D (PLD) 活性上调。已鉴定出两种不同的 PLD：PLD1 和 PLD2。然而，人们对每个 PLD 被激活的机制知之甚少。使用瞬时转染的人胚胎肾成纤维细胞 (HEK293)，我们在此证明 PLD1 活性以及较小程度的 PLD2 活性响应表皮生长因子 (EGF) 而受到刺激。 PLD2（而非 PLD1）以不依赖配体的方式与 EGF 受体结合，并在 EGF 受体激活后被酪氨酸磷酸化。 PLD2 的酪氨酸 11 (Tyr-11) 被确定为特定的磷酸化位点。该残基突变为苯丙氨酸使基础活性几乎提高了 2 倍，但没有改变 EGF 介导的 PLD2 活性增加的幅度。总之，我们在这里首次展示了激动剂刺激的 PLD1 和 PLD2 体内激活，并提供了每种亚型与 EGF 受体的不同类型相互作用的证据。此外，我们的结果表明激动剂诱导的酪氨酸磷酸化在 PLD2 调节中发挥作用。
Mammalian phospholipase D (PLD) activity becomes up-regulated when cells are stimulated by a variety of hormones, growth factors, and other extracellular signals. Two distinct PLDs, PLD1 and PLD2, have been identified. The mechanism through which each PLD is activated, however, is poorly understood. Using transiently transfected human embryonic kidney fibroblasts (HEK293), we demonstrate here that PLD1 activity, and to a lesser extent PLD2 activity, is stimulated in response to epidermal growth factor (EGF). PLD2, but not PLD1, associates with the EGF receptor in a ligand-independent manner and becomes tyrosine-phosphorylated upon EGF receptor activation. Tyrosine 11 (Tyr-11) of PLD2 was identified as the specific phosphorylation site. Mutation of this residue to phenylalanine enhanced basal activity almost 2-fold, but did not alter the magnitude of the EGF-mediated increase in PLD2 activity. In conclusion, we show here for the first time agonist-stimulated activation of both PLD1 and PLD2 in vivo and provide evidence of a distinct type of interaction for each isoform with the EGF receptor. Moreover, our results suggest that agonist-induced tyrosine phosphorylation plays a role in PLD2 regulation.