Abstract：
Receptor tyrosine kinases exhibit ligand-induced activity and uptake into cells via endocytosis. In the case of epidermal growth factor (EGF) receptor (EGFR), the resulting endosomes are trafficked to the perinuclear region, where dephosphorylation of receptors occurs, which are subsequently directed to degradation. Traveling endosomes bearing phosphorylated EGFRs are subjected to the activity of cytoplasmic phosphatases as well as interactions with the endoplasmic reticulum (ER). The peri-nuclear region harbors ER-embedded phosphatases, a component of the EGFR-bearing endosome-ER contact site. The ER is also emerging as a central player in spatiotemporal control of endosomal motility, positioning, tubulation, and fission. Past studies strongly suggest that the physical interaction between the ER and endosomes forms a reaction \"unit\" for EGFR dephosphorylation. Independently, endosomes have been implicated to enable quantization of EGFR signals by modulation of the phosphorylation levels. Here, we review the distinct mechanisms by which endosomes form the logistical means for signal quantization and speculate on the role of the ER.
摘要：
受体酪氨酸激酶表现出配体诱导的活性并通过胞吞作用摄取到细胞中。在表皮生长因子（EGF）受体（EGFR）的情况下，由此产生的内体被贩运到核周区域，发生受体去磷酸化的地方，随后被导向降解。携带磷酸化EGFR的行进内体经受细胞质磷酸酶的活性以及与内质网（ER）的相互作用。核周区藏有内质网包埋的磷酸酶，携带EGFR的内体-ER接触位点的一个组成部分。ER也正在成为内体运动性时空控制的中心角色，定位,插管,和裂变。过去的研究强烈表明，ER和内体之间的物理相互作用形成了EGFR去磷酸化的反应“单位”。独立地,内体被认为能够通过调节磷酸化水平来量化EGFR信号.这里,我们回顾了内体形成信号量化的后勤手段的不同机制，并推测了ER的作用。
