P-Rex1,一个PtdIns(3,4,5) P3-和Rac Rac的Gbetagamma调节的关氨核酸交换因子
Heidi C E Welch1, W John Coadwell, Christian D Ellson
1Inositide Laboratory, Cambridge CB2 4AT, United Kingdom.
Cell
|April 17, 2002
概括
研究人员确定了P-Rex1,一种新的Rac激活剂,对中性粒细胞信号传递至关重要. 这种关氨酸核酸交换因子 (GEF) 被特定的脂质和G蛋白子单元激活,影响细胞反应.
科学领域:
- 细胞生物学 细胞生物学
- 分子信号传输的方法
- 免疫学 免疫学 免疫学
背景情况:
- Rac GTPases是细胞过程的关键调节者.
- 中性粒细胞信号传递涉及复杂的细胞内通路.
- 酸和G蛋白在细胞激活中起着至关重要的作用.
研究的目的:
- 鉴定和描述中性粒细胞中Rac的新型激活剂.
- 为了阐明Rac激活的调节机制.
- 了解 Rac 信号在中性粒细胞功能中的作用.
主要方法:
- 从中性粒细胞醇中净化一个PtdIns(3,4,5) P3-敏感的Rac激活剂.
- 发现的蛋白质P-Rex1.1的克隆和重组表达.
- 在体外和体内测试以评估P-Rex1的关氨酸核酸交换因子 (GEF) 活性.
- 使用反感性寡核酸来评估P-Rex1在中性粒细胞类细胞中的功能.
主要成果:
- 一种名为P-Rex1的新型185 kDa GEF被净化并被确定为Rac激活剂.
- 素酸 (3,4,5) - 三酸 (PtdIns(3,4,5) P3) 和 Gbetagamma子单元直接,实质性和协同激活P-Rex1活动.
- 使用反感性寡核酸降低P-Rex1的下调,减少了对C5a刺激的反应性氧物种的形成.
- P-Rex1 作为 PtdIns ((3,4,5) P3 和 Gbetagamma 信号通路的巧合探测器.
结论:
- P-Rex1是一种新型的,关键的Rac氨酸核酸交换因子在中性粒细胞中.
- P-Rex1 集成了来自 PtdIns ((3,4,5) P3 和 Gbetagamma 路径的信号.
- P-Rex1在中性粒细胞激活中起着重要作用,特别是在对C5a.等化学吸引剂的反应中.
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...
Directionality of Nuclear Transport
Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...
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...
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:
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...


