インテグリン媒介の信号伝導は,GRB2が焦点粘着キナーゼと結合することで,Ras経路と結びついている
D D Schlaepfer1, S K Hanks, T Hunter
1Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92186.
Nature
|December 22, 1994
まとめ
フィブロネクチンがインテグリンと結合すると,焦点粘着キナーゼ (FAK) 信号伝達が活性化されます. これは細胞の結合を促進し,GRB2とc-Srcの相互作用を通じてRas/MAPK経路を活性化します.
科学分野:
- 細胞生物学 細胞生物学
- 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:
- 焦点粘着キナーゼ (FAK) は,細胞粘着部位におけるインテグリン受容体と局所化する細胞質タンパク質チロシンキナーゼ (PTK) である.
- インテグリンがフィブロネクチンなどの細胞外マトリックスタンパク質と結合すると,FAKのチロシンリン酸化が誘発されます.
研究 の 目的:
- インテグリン媒介シグナル伝達経路におけるFAK,GRB2,c-Srcの役割を調査する.
- インテグリンエンゲージメントとミトゲン活性化タンパク質キナーゼ (MAPK) アクティベーションを結びつけるメカニズムを解明する.
主な方法:
- フィブロネクチンに付着するNIH3T3線維芽細胞を研究した.
- タンパク質とタンパク質の相互作用を in vivo で評価するために共免疫プレシピテーションを使用した.
- 変異したFAKタンパク質で in vitro結合アッセイを行った.
主要な成果:
- ファイブロネクチン誘発の細胞結合は,GRB2とc-SrcがFAKと結合することを促進した.
- この関連性は,チロシンリン酸化FAK.に結合するGRB2のSH2ドメインによって媒介された.
- FAKチロシン925の変異はGRB2結合を阻害し,その重要な役割を示しています.
- フィブロネクチン刺激への反応として,MAPKの活性化が観察されました.
結論:
- インテグリンとフィブロネクチンとの結合は,FAK,c-Src,GRB2.2を含むシグナル伝達複合体を開始します.
- Tyr 925でのFAKリン酸化により,GRB2の結合部位が形成され,インテグリンシグナリングをRas/MAPK経路と結びつける.
関連する概念動画
The Ras Gene
The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
Ras is a superfamily...
Interactions Between Signaling Pathways
Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
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:
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...
Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...


