人間のGABA (B) 受容体におけるリガンド活性化の構造的メカニズム

Yong Geng¹, Martin Bush¹, Lidia Mosyak¹

¹Department of Pharmacology, Columbia University, New York, New York 10032, USA.

Nature

|December 6, 2013

まとめ

脳抑制に不可欠なヒトのGABA (B) 受容体を構造的に分析した. アゴニストは,GBR1ドメインを閉じることで活性化させ,新しいヘテロジマーインターフェースを明らかにします.

科学分野:

神経科学は神経科学である.
構造生物学構造生物学とは
バイオケミストリーバイオケミストリー

背景:

人間のGABA (B) 受容体は,抑制性神経伝達に不可欠なGタンパク質結合受容体である.
GBR1およびGBR2サブユニットからなる強制ヘテロダイマーとして機能します.

研究の目的:

GABA (B) 受容体活性化の構造的基礎を解明する.
受容体シグナル伝達に関与する形状の変化と相互作用を特徴付ける.

主な方法:

X線結晶学を用いて,GBR1-GBR2細胞外ドメインの構造を決定した.
アポ状態,アゴニスト状態,アンタゴニスト状態の構造が得られた.

主要な成果:

GBR1とGBR2の両方のサブユニットは,静止状態 (apoとantagonist-bound) で開いた形状を採用しています.
アゴニスト結合は,特にGBR1サブユニットでドメイン閉鎖を誘導し,活性状態を意味する.
アゴニストとアンタゴニストは,GBR1領域間裂け目内の重なり合っている部位に結合します.
活性化中に,GBR1とGBR2の間の新しいヘテロダイマーインターフェースが形成されます.

結論:

GABA(B) 受容体は,アゴニスト結合時にGBR1ドメインの閉鎖を含むユニークな活性化メカニズムを示しています.
構造的な洞察は,反抗体が不活性状態を安定させ,反抗体が活性化を促す方法を明らかにします.
特定されたヘテロダイマーインターフェースは,受容体の機能とシグナル伝達に不可欠です.

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