合作性自抑制和Vav1激活的结构和能量机制
Bingke Yu1, Ilídio R S Martins, Pilong Li
1Department of Biochemistry, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8816, USA.
Cell
|February 10, 2010
概括
蛋白质,关氨酸核酸交换因子 (GEFs) 是由一个自身抑制元素调节的. 结构和生物物理研究揭示了一个阶段性激活机制,涉及酸化依赖的域相互作用,用于GEF控制.
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:
- 瓦维蛋白作为Rho家族GTPases的关氨酸核酸交换因子 (GEFs) 起作用.
- 这些GEF是T细胞激活,细胞化和细胞迁移的关键调节者.
- 瓦维蛋白的失调与各种细胞过程和疾病有关.
研究的目的:
- 为了阐明Vav1蛋白的结构和自身抑制机制.
- 了解Vav1调节的生物物理和细胞基础.
- 调查Vav1如何实现强大的自身抑制和快速激活.
主要方法:
- 进行X射线晶体学以确定Vav1自身抑制元素的结构.
- 生物物理技术分析域互动和能量学.
- 细胞测试以评估Vav1功能和激活动力学.
主要成果:
- 在结构上表征了Vav1的五域自抑制元件.
- 确定了两个能量合的过程,控制Dbl同质 (DH) 催化域.
- 观察到自抑制的逐步缓解,由破坏域接触的酸化事件启动.
结论:
- Vav1自抑制涉及DH和Acidic域之间的核心相互作用,由calponin同质性 (CH) 域加强.
- 对CH域接触的酸化依赖的破坏促进了随后的激活.
- 这种机制允许精确控制Vav1活动,平衡抑制和快速激活.
相关概念视频
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
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...
Pinching-off of Coated Vesicles
Vesicle budding is orchestrated by distinct cytosolic proteins such as adaptor proteins, coat proteins, and GTPases. To initiate vesicle budding, membrane-bending proteins containing crescent-shaped BAR domains bind to the lipid heads in the bilayer and distort the membrane to form a protein-coated vesicle bud. Adaptors proteins such as AP2 for clathrin-coated vesicles can nucleate on the deformed membrane. Finally, coat proteins such as clathrin or COPI and COPII assemble into a coat forming...


