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Threonine phosphorylation regulates the molecular assembly and signaling of EGFR in cooperation with membrane lipids
bioRxiv - Biophysics Pub Date : 2021-12-17 , DOI: 10.1101/2021.05.14.444132
Ryo Maeda , Hiroko Tamagaki-Asahina , Takeshi Sato , Masataka Yanagawa , Yasushi Sako

The cytoplasmic domain of the receptor tyrosine kinases (RTKs) plays roles as a phosphorylation enzyme and a protein scaffold but the allocation of these two functions is not fully understood. We here analyzed assembly of the transmembrane (TM)-juxtamembrane (JM) region of EGFR, one of the best studied species of RTKs, by combining single-pair FRET imaging and a nanodisc technique. The JM domain of EGFR contains a threonine residue (Thr654) that is phosphorylated after ligand association. We observed that the TM-JM peptides of EGFR form anionic lipid-induced dimers and cholesterol-induced oligomers. The two forms involve distinct molecular interactions, with a bias towards oligomer formation upon threonine phosphorylation. We further analyzed the functions and oligomerization of whole EGFR molecules, with or without a substitution of Thr654 to alanine, in living cells. The results suggested an autoregulatory mechanism in which Thr654 phosphorylation causes a switch of the major function of EGFR from kinase activation dimers to scaffolding oligomers.

中文翻译:

苏氨酸磷酸化与膜脂协同调节 EGFR 的分子组装和信号传导

受体酪氨酸激酶 (RTK) 的细胞质结构域起到磷酸化酶和蛋白质支架的作用,但这两种功能的分配尚不完全清楚。我们在这里通过结合单对 FRET 成像和纳米盘技术分析了 EGFR 的跨膜 (TM)-近膜 (JM) 区域的组装,这是研究得最好的 RTK 物种之一。EGFR 的 JM 结构域包含一个苏氨酸残基 (Thr654),该残基在配体结合后被磷酸化。我们观察到 EGFR 的 TM-JM 肽形成阴离子脂质诱导的二聚体和胆固醇诱导的寡聚体。这两种形式涉及不同的分子相互作用,在苏氨酸磷酸化时偏向于形成寡聚体。我们进一步分析了整个EGFR分子的功能和寡聚化,在活细胞中用或不用 Thr654 替换为丙氨酸。结果表明一种自动调节机制,其中 Thr654 磷酸化导致 EGFR 的主要功能从激酶激活二聚体转变为支架寡聚体。
更新日期:2021-12-20
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