密切相关的ARF-GEF在蛋白质分泌和循环利用中的功能多样化
Sandra Richter1, Niko Geldner, Jarmo Schrader
1ZMBP, Entwicklungsgenetik, Tübingen, Germany.
Nature
|July 27, 2007
概括
瓜核化物交换因子 (ARF-GEFs),如Arabidopsis中的GNOM和GNL1,可以调节囊泡运输. GNL1保持了祖先的ER-Golgi贩运,而GNOM进化了额外的内体功能.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 植物生物学 植物生物学
背景情况:
- 在ADP-ribosylation factor GTPases (ARF-GEFs) 上的关氨酸核酸交换因子通过激活ARF基质来调节囊泡形成.
- 哺乳动物和酵母的ARF-GEF (GBF1,Gea1/2) 在戈尔吉膜上起作用,形成COPI涂层的囊泡.
- 阿拉比多普西斯GNOM (GN) 对于内体循环至关重要,这表明植物和动物之间的途径分歧.
研究的目的:
- 研究阿拉比多普西斯GNOM-LIKE1 (GNL1) 在内分泌网膜-戈尔吉运输中的作用.
- 了解ARF-GEF功能在植物贩运途径中的进化分歧.
- 为了比较GNL1和GNOM在Arabidopsis中的功能作用.
主要方法:
- 在Arabidopsis中对GNL1的局部化研究.
- 在囊泡形成和贩运中对GNL1和GNOM的功能分析.
- 在不同物种中对ARF-GEF同类物种进行比较分析.
主要成果:
- GNL1定位在Golgi堆中,并调节COPI涂层囊泡的形成,执行祖先的ER-Golgi贩运作用.
- 在功能上,GNOM可以替代GNL1,但GNL1不能替代GNOM的内体细胞循环功能.
- 阿拉比多普西斯利用GNL1和GNOM进行ER-Golgi运输,GNOM已经演变为一种额外的植物特异性作用.
结论:
- 大型ARF-GEF的GBF1类,包括GNL1和GNOM在Arabidopsis,执行保存ER-Golgi贩运.
- GNOM在内体循环中获得了植物特异性的功能,证明了贩运途径的独立演变.
- 植物中的ARF-GEF进化涉及重复和多样化,与ARF-GEF新类内体贩运的动物进化形成鲜明对比.
相关概念视频
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:


