Activity of EGFR transmembrane region variants indicates specific transmembrane dimers are not required for EGFR activity.
Activity of EGFR transmembrane region variants indicates specific transmembrane dimers are not required for EGFR activity.
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EGFR 跨膜区变体的活性表明 EGFR 活性不需要特定的跨膜二聚体。
DOI：
10.1042/bcj20220472
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Leahy,DanielJ
中科院分区：
文献类型：
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作者：
Bartzoka,Foteini;Gonzalez-Magaldi,Monica;Byrne,PatrickO;Callery,NicoleI;Hristova,Kalina;Leahy,DanielJ
表皮生长因子受体（EGFR）是一种受体酪氨酸激酶，在复杂生物体的发育和维持过程中介导细胞增殖和分化事件。特异性配体依赖性EGFR二聚体的形成是刺激EGFR信号传导的关键步骤，并且分离的EGFR胞外区和激酶结构域的活性二聚体形式的晶体结构已经揭示了关于二聚体相互作用如何调节EGFR活性的许多信息。然而，跨膜区在调节EGFR活性中的性质和作用仍然不太清楚。跨膜区的作用范围从非特异性但能量有利的相互作用到与EGFR的活性、非活性或活性调节状态相关的特异性跨膜二聚体构象。为了研究特异性跨膜二聚体在调节EGFR活性中的作用，我们产生了13种EGFR变体，其具有改变的跨膜序列，旨在有利于或不利于特定类型的跨膜区域相互作用。我们显示使用FRET显微镜，EGFR跨膜区域有内在的倾向，在哺乳动物细胞膜，这是抵消了细胞外区域。我们使用基于细胞的测定表明，除了导致组成性受体磷酸化的Neu变体之外，每个EGFR跨膜变体都能够自磷酸化并刺激下游效应物Erk和Akt的磷酸化。我们的研究结果表明，许多跨膜序列，包括聚亮氨酸，与EGFR的活性是兼容的，并没有提供证据，为特定的跨膜二聚体调节EGFR的功能。
The Epidermal Growth Factor Receptor (EGFR) is a Receptor Tyrosine Kinase that mediates cell proliferation and differentiation events during development and maintenance of complex organisms. Formation of specific, ligand-dependent EGFR dimers is a key step in stimulating EGFR signaling, and crystal structures of active, dimeric forms of isolated EGFR extracellular regions and kinase domains have revealed much about how dimer interactions regulate EGFR activity. The nature and role of the transmembrane region in regulating EGFR activity remains less clear, however. Proposed roles for the transmembrane region range from nonspecific but energetically favorable interactions to specific transmembrane dimer conformations being associated with active, inactive, or activity-modulated states of EGFR. To investigate the role of specific transmembrane dimers in modulating EGFR activity we generated thirteen EGFR variants with altered transmembrane sequences designed to favor or disfavor specific types of transmembrane region interactions. We show using FRET microscopy that EGFR transmembrane regions have an intrinsic propensity to associate in mammalian cell membranes that is counteracted by the extracellular region. We show using cell-based assays that each of the EGFR transmembrane variants except the Neu variant, which results in constitutive receptor phosphorylation, is able to autophosphorylate and stimulate phosphorylation of downstream effectors Erk and Akt. Our results indicate that many transmembrane sequences, including polyleucine, are compatible with EGFR activity and provide no evidence for specific transmembrane dimers regulating EGFR function.