Bidaux Gabriel, Sgobba Miriam, Lemonnier Loic, Borowiec Anne-Sophie, Noyer Lucile, Jovanovic Srdan, Zholos Alexander V, Haider Shozeb
Inserm, U1003, Laboratoire de Physiologie Cellulaire, Equipe labellisée par la Ligue contre le Cancer, Villeneuve d'Ascq, France; Laboratory of Excellence, Ion Channels Science and Therapeutics, Université de Lille 1, Villeneuve d'Ascq, France; Laboratoire Biophotonique Cellulaire Fonctionnelle. Institut de Recherche Interdisciplinaire, Villeneuve d'Ascq, France.
Centre for Cancer Research and Cell Biology, Queen's University of Belfast, Belfast, United Kingdom.
Biophys J. 2015 Nov 3;109(9):1840-51. doi: 10.1016/j.bpj.2015.09.027.
Members of the transient receptor potential (TRP) ion channel family act as polymodal cellular sensors, which aid in regulating Ca(2+) homeostasis. Within the TRP family, TRPM8 is the cold receptor that forms a nonselective homotetrameric cation channel. In the absence of TRPM8 crystal structure, little is known about the relationship between structure and function. Inferences of TRPM8 structure have come from mutagenesis experiments coupled to electrophysiology, mainly regarding the fourth transmembrane helix (S4), which constitutes a moderate voltage-sensing domain, and about cold sensor and phosphatidylinositol 4,5-bisphosphate binding sites, which are both located in the C-terminus of TRPM8. In this study, we use a combination of molecular modeling and experimental techniques to examine the structure of the TRPM8 transmembrane and pore helix region including the conducting conformation of the selectivity filter. The model is consistent with a large amount of functional data and was further tested by mutagenesis. We present structural insight into the role of residues involved in intra- and intersubunit interactions and their link with the channel activity, sensitivity to icilin, menthol and cold, and impact on channel oligomerization.
瞬时受体电位（TRP）离子通道家族成员作为多模式细胞传感器，有助于调节Ca(2+)稳态。在TRP家族中，TRPM8是形成非选择性同四聚体阳离子通道的冷感受器。由于缺乏TRPM8晶体结构，人们对其结构与功能之间的关系知之甚少。TRPM8结构的推断来自与电生理学相结合的诱变实验，主要涉及构成适度电压传感结构域的第四跨膜螺旋（S4），以及均位于TRPM8 C末端的冷感受器和磷脂酰肌醇4,5-二磷酸结合位点。在本研究中，我们结合分子建模和实验技术来研究TRPM8跨膜和孔螺旋区域的结构，包括选择性过滤器的传导构象。该模型与大量功能数据一致，并通过诱变进一步测试。我们展示了对参与亚基内和亚基间相互作用的残基的作用及其与通道活性、对艾西利定、薄荷醇和冷的敏感性以及对通道寡聚化的影响的结构见解。
