人类calpain-3及其结构可塑性:在结合titin上将同质合体分解成二元体
Qilu Ye1, Amy Henrickson2, Borries Demeler2
1Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
bioRxiv : the preprint server for biology
|March 11, 2024
概括
卡尔帕因-3,对于肌肉修复至关重要,形成不活跃的六合体,在结合丁后分离为活跃的二合体. 这种结构洞察力有助于理解四肢腰带肌肉发育不良.
科学领域:
- 分子和结构生物学 分子和结构生物学
- 肌肉生理学和疾病
背景情况:
- 卡尔巴因-3是骨肌中的依赖的蛋白酶,对于修复受损蛋白质至关重要.
- 卡尔帕因-3的突变会导致肢体腰带肌肉发育不良,已知有500多种人类变异.
- 独特的蛋白酶敏感序列 (NS,IS1,IS2) 复杂化了calpain-3的结构研究.
研究的目的:
- 阐明calpain-3的整体结构及其在疾病中的潜在作用.
- 研究突变如何影响calpain-3的活性和结构.
- 确定calpain-3的原生寡合体状态和组合.
主要方法:
- 在大肠杆菌中,稳定了calpain-3突变体 (ΔNS ΔIS1,C129A) 的重组表达.
- 使用尺寸排除色谱 (SEC-MALS),蓝色原生PAGE和分析超离心 (AUC) 的生物物理表征.
- 单粒子冷电子显微镜 (cryo-EM) 用于高分辨率的结构确定.
主要成果:
- 卡尔帕因-3始终形成一个大型0.5-MDa复合体,被确定为卡尔帕因-3二元体的三元体.
- 低温电磁探测揭示了一个六极形结构,其核心有六个五极形-EF-手域.
- 丁N2A区域的结合将复合体大小减少到320kDa的粒子,表明二聚体的形成.
结论:
- 卡尔帕因-3存在于其新合成的状态下作为一个不活跃的六合体.
- 与titin的N2A区域的相互作用触发了sarcomere内部分裂成活跃的calpain-3二元体.
- 这种结构机制为了解肌肉中的calpain-3功能和功能障碍提供了一个框架.
相关概念视频
Tension Response at Adherens Junctions
2.6K
The adherens junctions that anchor cells together are multi-protein complexes that dynamically adapt to mechanical stimuli such as tensile forces and shear stress. Mechanosensory proteins in these junctions can sense such mechanical stimuli and undergo a shift in their conformation, resulting in an altered function — a process called mechanotransduction.
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin...
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin...
2.6K
Disassembly of Intermediate Filaments
2.1K
Intermediate filaments (IFs) do not undergo spontaneous disassembly. Enzymes, kinases, and phosphatases add and remove phosphates from specific sites to regulate their disassembly. The IF concentration in the cytoplasm also regulates the disassembly. If the concentration crosses a threshold, it activates the protein kinases in the vicinity, allowing the phosphorylation of IFs.
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
Keratin proteins, found at the cell periphery near cell junctions, undergo a cycle of assembly and disassembly. In Type...
2.1K
Cytoskeletal Linker Proteins - Plakins
2.3K
Plakins are large proteins with binding domains for microtubules, microfilaments, intermediate filaments, and membrane-associated protein complexes at cell junctions. Plakin functions are evolutionarily conserved and are primarily involved in organizing the different components of the cytoskeleton by crosslinking them to each other and connecting them to the cell-matrix and cell adhesion complexes. They are also known to interact with signal transducers, serve as scaffolds for signaling...
2.3K
Structural Protein Function
27.6K
Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures such as bones, cartilage, hair, and muscles. This group includes proteins such as collagen, actin, myosin, and keratin.
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to...
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to...
27.6K
Catenins
2.3K
Catenins are characterized by multiple binding domains and dynamic structures that allow them to function as linker proteins in cell junction complexes. All catenins, except α-catenin, contain a characteristic protein sequence called the armadillo repeat and are therefore also called armadillo proteins.
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the...
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the...
2.3K
Actin Filament Depolymerization
3.1K
Actin filaments (F-actin) are composed of actin subunits. The dissociation of actin monomers can occur from either end of F-actin. The rate of dissociation is faster from the minus-end or the pointed end, where the actin subunits exist with a bound ADP, together known as ADP-actin. The depolymerization of F-actin is aided by proteins, including the actin-depolymerizing factor (ADF) and cofilin family of proteins, gelsolin, and glia maturation factor (GMF).
In F-actin, the ADF/cofilin proteins...
In F-actin, the ADF/cofilin proteins...
3.1K


