小型GTPase rab5は,初期の内細胞経路の調節因子として機能する
C Bucci1, R G Parton, I H Mather
1European Molecular Biology Laboratory, Heidelberg, Germany.
Cell
|September 4, 1992
まとめ
Rab5は,初期のエンドソームの重要なタンパク質で,膜の交通を調節する. その突然変異は内細胞化を遅らせ,正常なRab5は加速し,速度を制限する役割を強調する.
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.
- メンブラン密輸 膜密輸
背景:
- Rab5は,初期のエンドソーム機能と膜密輸に不可欠な小さなGTPaseである.
- Rab5のインビヴォの役割を理解することは,内細胞経路の調節を解読するために不可欠です.
研究 の 目的:
- 初期の内細胞経路におけるRab5のインビボ機能的役割を調査する.
- Rab5がエンドサイトーシスと膜交通運動に与える影響を決定する.
主な方法:
- 野生型および変異性 (rab5-ile133) Rab5タンパク質の過剰発現が赤ちゃんハムスターの腎臓細胞に.
- エンドサイトーシスとリサイクル率の評価.
- 初期のエンドソームの形態論を分析する.
主要な成果:
- ミュータントの rab5-ile133は,リサイクルに影響を与えることなく,エンドサイトーシス率を50%大幅に低下させた.
- ミュータントRab5は,外周管と膀を持つ異常な早期エンドソーム形態を誘発した.
- 野生型のRab5過剰発現は,内細胞マーカーの吸収を加速し,早期エンドソームを拡大した.
結論:
- Rab5は,初期の内細胞経路における速度制限因子である.
- Rab5は膜交通の動力学に直接影響を及ぼします.
- Rab5のGTP結合活動は,エンドサイトーシスにおけるその機能に極めて重要です.
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...
Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
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:


