MHCでコードされたプロテアゾームサブユニットは,MHCクラスI分子に結合したペプチドの処理に通常必要とされません
D Arnold1, J Driscoll, M Androlewicz
1Division of Tumor Virology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115.
Nature
|November 12, 1992
まとめ
この研究は,プロテアソームが抗原処理に欠かせないことを示しています. 重要なプロテアソーム成分 (LMP2およびLMP7) を欠いた場合でも,細胞はペプチドを主要な組織適合性複合体のクラスI分子を介して提示することができます.
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.
- プロテアゾームの機能
背景:
- メジャー・ヒストコンパティビリティ・コンプレックス (MHC) クラスIの分子は,細胞毒性Tリンパ球にペプチドを提示し,細胞免疫における重要なステップである.
- これらのペプチドの生成とシトゾールからエンドプラズマ網膜への配送には,TAP1-TAP2トランスポーターが関与します.
- プロテアソームのサブユニットであるLMP2とLMP7は,TAP遺伝子の近くに位置しており,抗原処理に関与しているという仮説を立てている.
研究 の 目的:
- 抗原処理経路におけるプロテアソームサブユニットLMP2およびLMP7の役割を調査する.
- プロテアソームがMHCクラスI分子によって提示されるペプチドの生成に不可欠であるかどうかを決定する.
主な方法:
- LMP2およびLMP7発現が欠けているヒトリンパ芽細胞系変異体 (721.174) を利用した.
- 変異細胞系における安定して組み立てられたMHCクラスI分子の発現を評価した.
- LMP7のアイデンティティは,遺伝子転送によるプロテアソマルサブユニットを再構成することによって確認されました.
主要な成果:
- MHCクラスI分子発現と正常なペプチド処理の完全な回復は,LMP2とLMP7が欠けている細胞で観察されました.
- 遺伝子転送により,プロテアソマルサブユニットが成功裏に再構成され,LMP7の同一性が確認されました.
- これらの発見は,抗原処理のこの側面におけるプロテアソームの推定された重要な役割に異議を唱える.
結論:
- プロテアソーム,特にLMP2およびLMP7サブユニットは,MHCクラスI分子によって提示されるペプチドの生成に不可欠ではありません.
- この研究は,原始抗原処理経路におけるプロテアゾームの仮説的関与を否定している.
- LMP2とLMP7が抗原処理における潜在的,より微妙な役割を完全に排除することはできません.
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