ベータ2インテグリンCR3 (CD11b/CD18) のAドメインにある新しい二価カチオン結合部位は,リガンド結合に不可欠である

M Michishita¹, V Videm, M A Arnaout

¹Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown 02129.

Cell

|March 26, 1993

まとめ

研究者らは,補完体受容体3型 (CR3) のCD11b A領域に新しいマンガン結合部位を発見した. この部位はCR3にとって極めて重要です.

科学分野:

免疫学免疫学とは
分子生物学は分子生物学である.
バイオケミストリーバイオケミストリー

背景:

コンプリメント受容体3型 (CR3) は,炎症と病原体認識に関与する重要な免疫受容体です.
CR3の機能は二価イオンによって調節されていることが知られているが,特定の金属結合部位は完全に特徴づけられていない.

研究の目的:

CR3.3のCD11b A領域内の金属結合部位を特定し,特徴づけること.
この金属結合部位がCR3媒介リガンド結合における役割を調査する.

主な方法:

マンガン (Mn2+) 結合を研究するために,CD11b Aドメインをコードする再結合ペプチドを使用しました.
金属結合に関与する重要なアミノ酸残基を特定するために,サイト・ダイレクト・ミュータゲネシスを実行しました.
完全なCR3受容体に突然変異を導入し,iC3b結合への影響を評価しました.

主要な成果:

新しいMn2+結合部位がCD11b Aドメイン内で特定され,Mn2+に高い親和性が認められた.
特定のアミノ酸置換により,再結合ペプチドへのMn2+結合が廃止されました.
これらの変異はまた,受容体発現やサブユニット関連に影響を与えることなく,CR3のiC3bへの金属依存結合を廃止しました.

結論:

CR3.3のCD11b A領域で,新しい,予期せぬ金属結合部位を特定しました.
この部位は,CR3とそのリガンド,iC3bの金属依存結合に不可欠です.
この発見は,CR3媒介の炎症を調節することを目的とした治療戦略の潜在的なターゲットを提供します.

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