Rag GTPasesはラプターに結合し,mTORC1へのアミノ酸シグナル伝達を媒介する
Yasemin Sancak1, Timothy R Peterson, Yoav D Shaul
1Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology (MIT), Nine Cambridge Center, Cambridge, MA 02142, USA.
まとめ
Ragタンパク質は,アミノ酸への反応としてmTORC1経路を活性化するために不可欠です. これらのGTPasesはmTORC1の局所化を媒介し,細胞成長とがん経路に影響を与えます.
科学分野:
- 分子生物学は分子生物学である.
- セルラー・シグナリング
- バイオケミストリー バイオケミストリー
背景:
- ラパミシン複合体1 (mTORC1) 経路のメカニスティックターゲットは,細胞の成長を調節する.
- この経路は,アミノ酸,インスリン,エネルギーレベルなどの栄養素に反応する.
- mTORC1の調節不全は,様々ながんに起因している.
研究 の 目的:
- mTORC1経路の活性化におけるRagタンパク質の役割を調査する.
- アミノ酸がラグタンパク質を通してmTORC1.1.へのシグナルをどのように伝達するかを決定する.
- ラグ媒介 mTORC1 調節のメカニズムを解明する.
主な方法:
- 変異したRagタンパク質 (GTP結合およびGDP結合) を利用してmTORC1の活性を調べた.
- mTORC1経路の活性化と細胞内局在性を評価した.
- ラグタンパク質とmTORC1.1.の相互作用を調査しました.
主要な成果:
- ラグタンパク質は,mTORC1とアミノ酸依存の形で相互作用する.
- 構成的に活性なGTP結合Ragタンパク質は,アミノ酸とは独立してmTORC1を活性化させる.
- GDPに結合したラグタンパク質は,アミノ酸刺激によるmTORC1の活性化を阻害する.
- ラグタンパク質は,mTORC1の局所化を,そのアクティベーターであるRhebとのコンパートメントに容易にします.
結論:
- ラグタンパク質は,mTORC1.1.へのアミノ酸シグナル伝達の重要なメディエーターである.
- ラグタンパク質は,mTORC1.1.の適切な細胞内局所化を促すことで機能します.
- Rag-mTORC1の相互作用を理解することは,がんの成長経路をターゲットにするための鍵です.
関連する概念動画
PI3K/mTOR/AKT Signaling Pathway
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a rapamycin-insensitive companion...
mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
MAPK Signaling Cascades
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...


