小さなGTPase Rab9の膜標的化は,ニュクレオチド交換が伴います
T Soldati1, A D Shapiro, A B Svejstrup
1Department of Biochemistry, Stanford University School of Medicine, California 94305-5307.
Nature
|May 5, 1994
まとめ
Rab9のようなラブタンパク質は,膀の輸送に不可欠です. この研究では,プレニル化Rab9が遅いエンドソームを選択的に標的にし,適切な機能のためにGDPからGTPの交換を誘発することを示しています.
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:
- Rab GTPasesは膀輸送を調節し,一部はGDPとGDIに結合する細胞溶液に含まれています.
- Rab9は特に後期エンドソームに局所化し,マノース6リン酸受容体のトランス・ゴルギネットワークへの輸送を容易にする.
- GDIによるラブタンパク質膜配送は,プリニレーションおよび構造的決定因子とともに,GDP-GTP交換を含むと仮定されています.
研究 の 目的:
- プレニル化Rab9.9の選択的膜標的を復元するために.
- Rab9の局所化におけるエンドソーム誘発の核酸交換の役割を調査する.
主な方法:
- プレニル化ラブ9タンパク質の選択的標的化が末期エンドソーム膜に再構成される.
- Rab9の膜結合中のニュクレオチド交換の分析.
主要な成果:
- プレニル化Rab9の選択的ターゲティングを後期エンドソームに成功裏に再構成した.
- このターゲティングプロセスには,エンドソームが誘発する核酸交換が伴っていることが実証されました.
結論:
- プレニル化Rab9は,後期エンドソーム膜を選択的に標的にすることができる.
- エンドソーム誘発の核酸交換は,Rab9の局所化と機能における重要な出来事です.
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...
Tail-anchoring of Proteins in the ER Membrane
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
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:


