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キーワード
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ジャーナル
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Structure paper

タイトル	Opening of the human epithelial calcium channel TRPV6.
ジャーナル・号・ページ	Nature, Vol. 553, Issue 7687, Page 233-237, Year 2018
掲載日	2018年1月11日
著者	Luke L McGoldrick / Appu K Singh / Kei Saotome / Maria V Yelshanskaya / Edward C Twomey / Robert A Grassucci / Alexander I Sobolevsky /
PubMed 要旨	Calcium-selective transient receptor potential vanilloid subfamily member 6 (TRPV6) channels play a critical role in calcium uptake in epithelial tissues. Altered TRPV6 expression is associated with ...Calcium-selective transient receptor potential vanilloid subfamily member 6 (TRPV6) channels play a critical role in calcium uptake in epithelial tissues. Altered TRPV6 expression is associated with a variety of human diseases, including cancers. TRPV6 channels are constitutively active and their open probability depends on the lipidic composition of the membrane in which they reside; it increases substantially in the presence of phosphatidylinositol 4,5-bisphosphate. Crystal structures of detergent-solubilized rat TRPV6 in the closed state have previously been solved. Corroborating electrophysiological results, these structures demonstrated that the Ca selectivity of TRPV6 arises from a ring of aspartate side chains in the selectivity filter that binds Ca tightly. However, how TRPV6 channels open and close their pores for ion permeation has remained unclear. Here we present cryo-electron microscopy structures of human TRPV6 in the open and closed states. The channel selectivity filter adopts similar conformations in both states, consistent with its explicit role in ion permeation. The iris-like channel opening is accompanied by an α-to-π-helical transition in the pore-lining transmembrane helix S6 at an alanine hinge just below the selectivity filter. As a result of this transition, the S6 helices bend and rotate, exposing different residues to the ion channel pore in the open and closed states. This gating mechanism, which defines the constitutive activity of TRPV6, is, to our knowledge, unique among tetrameric ion channels and provides structural insights for understanding their diverse roles in physiology and disease.
リンク	Nature / PubMed:29258289 / PubMed Central
手法	EM (単粒子)
解像度	3.6 - 4.2 Å
構造データ	7120 6bo8 EMDB-7120, PDB-6bo8: Cryo-EM structure of human TRPV6 in nanodiscs 手法: EM (単粒子) / 解像度: 3.6 Å 7121 6bo9 EMDB-7121, PDB-6bo9: Cryo-EM structure of human TRPV6 in amphipols 手法: EM (単粒子) / 解像度: 4.0 Å 7122 6boa EMDB-7122, PDB-6boa: Cryo-EM structure of human TRPV6-R470E in amphipols 手法: EM (単粒子) / 解像度: 4.2 Å 7123 6bob EMDB-7123, PDB-6bob: Cryo-EM structure of rat TRPV6* in nanodiscs 手法: EM (単粒子) / 解像度: 3.9 Å
由来	homo sapiens (ヒト) rattus norvegicus (ドブネズミ)
キーワード	TRANSPORT PROTEIN / Ion channel / Membrane protein