Endosomal localization and receptor dynamics determine tyrosine phosphorylation of hepatocyte growth factor-regulated tyrosine kinase substrate
Endosomal localization and receptor dynamics determine tyrosine phosphorylation of hepatocyte growth factor-regulated tyrosine kinase substrate
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DOI：
10.1128/mcb.20.20.7685-7692.2000
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发表时间：
2000-10-01
影响因子：
5.3
通讯作者：
Clague, MJ
中科院分区：
文献类型：
--
作者：
Urbé, S;Mills, IG;Clague, MJ
肝细胞生长因子调节的酪氨酸激酶底物（Hrs）是激活酪氨酸激酶受体的主要底物，已被认为在内体膜运输中发挥作用。该蛋白含有FYVE结构域，其特异性结合脂质磷脂酰肌醇（PI）3-磷酸（PI 3-P）。我们表明，这种相互作用是必需的正确定位的蛋白质的内体，只有部分符合早期内体自身抗原1和有效的酪氨酸磷酸化的蛋白质在表皮生长因子刺激。用渥曼青霉素处理揭示了Hrs磷酸化也需要PI 3-激酶活性，这对于产生定位所需的PI 3-P是必要的。我们已经使用高渗介质和表达的显性负形式的发动蛋白（K44 A），以抑制内吞作用，在这种条件下，受体刺激未能引起磷酸化的Hrs。我们的研究结果提供了一个明确的例子，耦合的信号转导通路的内吞作用，从我们提出，激活的受体（或相关因子）必须交付到适当的内吞隔室，以Hrs磷酸化发生。
Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) is a prominent substrate for activated tyrosine kinase receptors that has been proposed to play a role in endosomal membrane trafficking. The protein contains a FYVE domain, which specifically binds to the lipid phosphatidylinositol (PI) 3-phosphate (PI 3-P). We show that this interaction is required both for correct localization of the protein to endosomes that only partially coincides with early endosomal autoantigen 1 and for efficient tyrosine phosphorylation of the protein in response to epidermal growth factor stimulation. Treatment with wortmannin reveals that Hrs phosphorylation also requires PI 3-kinase activity, which is necessary to generate the PI 3-P required for localization. We have used both hypertonic media and expression of a dominant-negative form of dynamin (K44A) to inhibit endocytosis; under which conditions, receptor stimulation fails to elicit phosphorylation of Hrs. Our results provide a clear example of the coupling of a signal transduction pathway to endocytosis, from which we propose that activated receptor (or associated factor) must be delivered to the appropriate endocytic compartment in order for Hrs phosphorylation to occur.