通过DOCK交换因子激活Rho GTPases是由一个核酸传感器介导的
Jing Yang1, Ziguo Zhang, S Mark Roe
1Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK.
概括
DOCK9-Cdc42复合体揭示了一种用于Rho GTPase激活的新型核酸传感器机制. 这种传感器促进了瓜二酸盐的释放和瓜三酸盐的排出,澄清了瓜核酸交换因子的催化循环.
科学领域:
- 分子生物学分子生物学
- 细胞信号传递 细胞信号传递
- 结构生物学 结构生物学
背景情况:
- 罗瓜诺辛三酸酶 (GTPases) 调节细胞骨和细胞信号传递.
- DOCK家族的关氨酸核酸交换因子 (GEFs) 激活Rho GTPases.
- 在此之前,DOCK GEF催化DHR2域的激活机制是未知的.
研究的目的:
- 为了阐明由DOCK家族GEFs激活Rho GTPase的机制.
- 确定通过DHR2域介导的关氨酸核酸交换的结构基础.
主要方法:
- 对DOCK9-Cdc42复合物的结构分析.
- 生物化学试验研究核酸释放和GTPase激活.
主要成果:
- 在DHR2域的alpha10螺旋中确定了一个核酸传感器.
- 这种传感器对于瓜二酸盐 (GDP) 的释放和随后的激活Cdc42-瓜三酸盐 (GTP) 的释放至关重要.
- 的排斥,通过保存的氨酸介导,促进GDP的释放,而GTP-Mg2+的结合会诱导GTPase释放的传感器位移.
结论:
- 通过DOCK GEFs发现了GDP释放和GTPase激活的不寻常机制.
- 已经定义了DOCK GEFs的完整催化循环,从GDP分离到GTP绑定和释放.
相关概念视频
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:
Rab Proteins
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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.
Activation and Inactivation of G Proteins
Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...
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...
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...


