Regulation of EGF receptor trafficking fate by phosphorylation and Odin

生长因子与受体的结合是调节后生动物生长和发育的关键机制。表皮生长因子受体（EGFR）是一种典型的生长因子受体。活化的EGFR通过内吞作用迅速内化。内化的EGFR或者再循环回到细胞表面，或者作为运输分选开关的结果在溶酶体中降解。EGFR还响应于细胞应激而内化和再循环。这些过程控制在细胞表面的受体密度，并反过来对不同的配体浓度梯度和环境信号的反应，这是高度可变的后生动物。我们的长期目标是了解在定量机制方面，如何动态共价修饰和蛋白质相互作用控制的贩运命运的生长因子受体。 我们发现EGFR磷酸化（Y 998，S1039）和蛋白Odin作为影响EGFR运输的因素。例如，未能在Y 998磷酸化活化的EGFR导致再循环，而没有Odin的细胞缺乏EGFR再循环。受体运输的调节已经被深入研究，但EGFR磷酸化如何调节其降解或降解运输命运的分子机制细节尚不清楚。我们的近期目标是确定磷酸化介导的EGFR分选的分子机制，构成一个清除或降解开关。 为此，我们提出以下具体目标： 目的1：解决测试Odin在EGFR再循环中的作用的问题：（A）Odin是否结合Y 998进行再循环，而不是刺激降解的pY 998？(B)Odin是否在应激诱导的EGFR再循环中起作用？(C)Odin的磷酸化是否调节其与EGFR的相互作用？ 目的2：检测EGFR-S1039磷酸化是否控制EGFR再循环，并阻止转运至溶酶体。(A)EGFR回收需要S1039吗？(B)受体相关磷酸酶是否调节S1039磷酸化，从而调节EGFR的再循环？(C)确定EGFR-S1039磷酸化的时间和空间调节，以确定其在回收中的作用。 对磷酸化/Odin介导的EGFR分选机制的理解将导致未来研究受体运输如何调节复杂生物体中的生长因子和环境信号。该计划还将有助于HQP在分子和细胞生物学以及蛋白质组学领域的培训。

Binding of growth factors to receptors is a key mechanism that regulates the growth and development of metazoans. Epidermal growth factor receptor (EGFR) is a prototypical growth factor receptor. Activated EGFR is rapidly internalization by endocytosis. Internalized EGFR either recycle back to the cell surface or degrade in lysosomes as a consequence of a trafficking sorting switch. EGFR also internalize and recycle in response to cellular stresses. These processes control receptor density at the cell surface, and in turn signaling responses to diverse ligand concentration gradients and environmental cues, which are highly variable in metazoans.Our long term objective is to understand in quantitative mechanistic terms, how dynamic covalent modifications and protein interactions control the trafficking fate of growth factor receptors. We discovered EGFR phosphorylations (Y998, S1039) and the protein Odin as factors affecting EGFR trafficking. For example, failure to phosphorylate activated EGFR at Y998 causes recycling, whereas cells without Odin lack EGFR recycling. Regulation of receptor trafficking has been intensively studied, but molecular mechanistic details of how EGFR phosphorylation regulates its recycle-or-degrade trafficking fate are not known. Our near term objective is to determine the molecular mechanism of phosphorylation-mediated EGFR sorting that constitutes a recycle-or-degrade switch. To achieve this, we propose the following specific aims: Aim 1: Address questions that test Odin’s role in EGFR recycling: (A) Does Odin bind Y998 for recycling, but not pY998, which stimulates degradation? (B) Does Odin function in stress-induced EGFR recycling? (C) Does phosphorylation of Odin modulate its interaction with EGFR? Aim2: Test if EGFR-S1039 phosphorylation controls EGFR recycling, and prevents transport to the lysosome. (A) Is S1039 required for EGFR recycling? (B) Does a receptor-associated phosphatase modulate S1039 phosphorylation, and consequently EGFR recycling? (C) Determination of temporal and spatial regulation of EGFR-S1039 phosphorylation towards defining its role in recycling. A mechanistic understanding phosphorylation/Odin-mediated EGFR sorting will lead to future studies of how receptor trafficking modulates growth factor and environmental signals in complex organisms. This program will also contribute to the training of HQP in the fields of molecular and cell biology, and proteomics.