小型GTPase rab5作为早期内细胞通路的调节因子
C Bucci1, R G Parton, I H Mather
1European Molecular Biology Laboratory, Heidelberg, Germany.
Cell
|September 4, 1992
概括
Rab5是早期内体中的关键蛋白质,它调节了膜交通. 它的突变减缓了内细胞分裂,而正常的Rab5则加速了内细胞分裂,突出了其限制速度的作用.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 膜贩运活动 膜贩运
背景情况:
- Rab5是一种小GTPase,对早期内体功能和膜贩运至关重要.
- 了解Rab5在体内发挥的作用对于破译内细胞通路调节至关重要.
研究的目的:
- 调查Rab5在早期内细胞通路中的体内功能作用.
- 确定Rab5对内分细胞和膜流动动学的影响.
主要方法:
- 在婴儿仓鼠细胞中过度表达野生类型和突变 (rab5-ile133) Rab5蛋白.
- 评估细胞内和循环利用率.
- 分析早期的内体细胞形态.
主要成果:
- 突变的rab5-ile133显著降低了50%,而不会影响回收.
- 突变Rab5诱导了异常的早期内分体形态与外周管道和囊泡.
- 野生类型的Rab5过度表达加速了内细胞标记物的吸收,并扩大了早期内基因组.
结论:
- Rab5是早期内细胞通路中的速度限制因素.
- Rab5直接影响膜流量的动力学.
- Rab5的GTP结合活性对于其在内细胞分裂中的功能至关重要.
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...
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:


