タンパク質分泌とリサイクルにおける密接に関連したARF-GEFの機能的多様化
Sandra Richter1, Niko Geldner, Jarmo Schrader
1ZMBP, Entwicklungsgenetik, Tübingen, Germany.
Nature
|July 27, 2007
まとめ
アラビドプシスのGNOMとGNL1のようなグアニン核酸交換因子 (ARF-GEF) は,膀輸送を調節する. GNL1は祖先のER-Golgiのトラフィックを維持し,GNOMは追加のエンドソーム機能を進化させた.
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.
- 植物生物学 植物生物学
背景:
- ADP-リボシライゼーション因子GTPases (ARF-GEFs) に関するグアニン核酸交換因子は,ARF基板を活性化することによって,膀形成を調節する.
- 哺乳類および酵母類のARF-GEFs (GBF1,Gea1/2) は,COPIでコーティングされた膀形成のためのゴルギ膜で機能する.
- アラビドプシスGNOM (GN) は,植物と動物の経路の相違を示し,エンドソームの循環に不可欠です.
研究 の 目的:
- アラビドプシスGNOM-LIKE1 (GNL1) のエンドプラズマ網膜-ゴルギ輸送における役割を調査する.
- 植物密輸経路におけるARF-GEF機能の進化的分岐を理解する.
- アラビドプシスのGNL1とGNOMの機能的役割を比較する.
主な方法:
- アラビドプシスのGNL1の局所化研究.
- GNL1とGNOMの機能分析. 膀形成と取引におけるGNL1とGNOMの機能分析.
- 種別におけるARF-GEFの同類体の比較分析.
主要な成果:
- GNL1はゴルギのスタックに局所化し,COPIで覆われた膀の形成を調節し,先祖のER-ゴルギの密輸役割を果たします.
- GNOMはGNL1を機能的に置き換えることができますが,GNL1はGNOMの内分体リサイクル機能を置き換えることはできません.
- アラビドプシスは,GNL1とGNOMをER-Golgi輸送に利用し,GNOMは植物特有の役割も進化した.
結論:
- アラビドプシスのGNL1とGNOMを含むGBF1クラスの大型ARF-GEFは,保存されたER-Golgiの密輸を行っています.
- GNOMは,エンドソームリサイクルにおける植物特有の機能を獲得し,密輸経路の独立した進化を示しています.
- 植物におけるARF-GEFの進化には,重複と多様化が伴うが,動物におけるARF-GEFの進化とは対照的である.
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...
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.
Assembly of Signaling Complexes
Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
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:


