Rab5は,受容体チロシンキナーゼによるアクチン改造に関与するシグナル伝達GTPaseである
Letizia Lanzetti1, Andrea Palamidessi, Liliana Areces
1Istituto Europeo di Oncologia, Via Ripamonti 435, 20141 Milan, Italy.
Nature
|May 21, 2004
まとめ
Rab5 GTPaseは,細胞内トラフィックとアクチンリモデリングを制御する. そのエフェクターであるRN-treは,マクロピノサイトーシスにとって極めて重要であり,Rab5をアクチン細胞骨格と結びつけ,重要な信号伝達経路を明らかにする.
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:
- 小さなGTPaseであるRab5は,細胞内トラフィックとエンドソームの動態を調節する.
- レセプターチロシンキナーゼ (RTK) は Rab5 を活性化させ,RTK エフェクタ経路におけるその役割の調査を促します.
研究 の 目的:
- Rab5がRTK誘発のエフェクタ経路に参加するかどうかを判断する.
- Rab5がアクチンの改造に影響を与える分子メカニズムを解明する.
主な方法:
- RTK誘発のアクチン改造,特に円形のラフリングにおけるRab5の役割を調査した.
- 特定されたRN-treは,Rab5固有のGTPase活性化タンパク質 (GAP) と効果因子である.
- マクロピノシトーシスにおけるRN-treの機能と,F-アクチンとアクチニン-4との相互作用を調べました.
主要な成果:
- Rab5は,RTK誘発の円形ラッフリングに不可欠であり,Rab5,フォスファティジル・イノシトール-3-OHキナーゼ,およびRac.から同時に信号が要求されます.
- RN-treはRab5-GAPとエフェクタの両方として作用し,Rab5のシグナル伝達をアクチン細胞骨格に媒介する.
- RN-treはマクロピノシトーシスにとって重要であり,F-アクチンとアクチニン-4と相互作用し,アクチンネットワーク形成における役割を示唆しています.
結論:
- Rab5はRTK経路におけるGTPアゼシグナルとして機能する.
- RN-treはRab5の重要な下流エフェクタであり,アクチン細胞骨格の動態とマクロピノサイトーシトーシスに関連付けています.
- Rab5-RN-tre-actin経路は,円形のラッフリングやマクロピノサイトーシトーシスなどの細胞プロセスに不可欠です.
さらに関連する動画
11:28Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates
Published on: March 31, 2012
13:51Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay
Published on: November 11, 2018
関連する概念動画
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
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...
