从人类玛管的晶体结构中了解微管核的洞察力
Hector Aldaz1, Luke M Rice, Tim Stearns
1Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, 600 16th Street, San Francisco, California 94143, USA.
Nature
|May 27, 2005
概括
人类马管素对于微管核形成至关重要,采用曲线形状. 它的晶体结构揭示了玛-氨酸环复合体 (gamma-TuRC) 如何可能模拟新的微管组件.
科学领域:
- 细胞生物学 细胞生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 微管子是alphabeta-tubulin的聚合物,对于真核细胞骨至关重要,并表现出GTP依赖的组装动态.
- 在体内微管细胞核形成需要马-氨酸,它是在马-氨酸环复合体 (gamma-TuRC) 中组织的.
- 关于马管素的寡合化及其促进微管组装的机制,存在有限的结构信息.
研究的目的:
- 阐明马管素寡合化的结构基础及其在微管核形成中的作用.
- 为了研究人类马管素与GTP-gammaS.结合时的形状.
主要方法:
- 确定了与GTP-gammaS.S.复合的人类玛布林的2.7-晶结构.
- 分析了晶体包装相互作用,以推断马-氨酸寡合化和横向关联.
主要成果:
- 观察到人类玛-氨酸-GTPgammaS的"曲"形状,类似于非聚合的alphabeta-tubulin.
- 晶体包装揭示了模仿微管结构的横向接触,这表明了玛-TuRC中玛-布林寡合化的基础.
- 该结构展示了侧面相关的玛氨酸如何通过增强alphabeta-tubulin异构体相互作用来模拟微管核形成.
结论:
- 马管素的曲形状及其形成横向关联的能力是其在微管细胞核中的功能关键.
- 玛-氨酸环复合体可能充当模板,促进alphabeta-氨酸异构体组装成新的微管.
- 这项研究透露了一种独特的功能性质,通过观察到的横向阵列的马-tubulins.
相关概念视频
Microtubules
There are three types of cytoskeletal structures in eukaryotic cells—microfilaments, intermediate filaments, and microtubules. With a diameter of about 25 nm, microtubules are the thickest of these fibers. Microtubules carry out a variety of functions that include cell structure and support, transport of organelles, cell motility (movement), and the separation of chromosomes during cell division.
Microtubules
Microtubules are the thickest cytoskeletal filaments with a diameter of 25 nm. In prokaryotic organisms, microtubules are commonly found in locomotory appendages like cilia and flagella. In eukaryotic cells, microtubules form specialized extensions for moving fluid over the surface, like those found in cells lining the intestine.
Microtubules have two structurally similar globular protein subunits: α and β tubulins. In the cytosol, the α and β tubulins form a heterodimer. These αβ-heterodimers...
Microtubules have two structurally similar globular protein subunits: α and β tubulins. In the cytosol, the α and β tubulins form a heterodimer. These αβ-heterodimers...
Microtubule Instability
Microtubules are hollow cylindrical filaments having a diameter of approximately 25 nm and a length that varies from 200 nm to 25 μm. GTP-bound tubulin subunits form αβ-heterodimers for microtubule assembly. These core building blocks interact longitudinally, polymerizing into protofilaments. The protofilaments then interact with one another through lateral bonding forces to form stable cylindrical microtubules. These cylindrical filaments are dynamic as they undergo repeated assembly and...
Microtubule Formation
Microtubules are dynamic structures that undergo continuous assembly and disassembly. They originate from specialized multi-protein complexes known as microtubule organizing centers or MTOCs. Within the MTOC, the point of origin of the microtubule is known as the minus end, while the end radiating outward is the plus end. Microtubules serve two primary functions — the organization of spindle complexes to separate sister chromatids during mitotic or meiotic cell division and the formation of...
Assembly of Complex Microtubule Structures
Complex microtubule structures are present in resting cells and in dividing cells. In resting cells, they are responsible for maintaining the cellular architecture, tracks for intracellular transport, positioning of organelles, assembly of cilia and flagella. They mediate the bipolar spindle assembly for chromosomal segregation and positioning of the cell division plate in dividing cells. The formation of microtubule complex structures depends on the cell type, cell stage, and cell function.
Microtubule Instability
Microtubules are hollow cylindrical filaments having a diameter of approximately 25 nm and a length that varies from 200 nm to 25 μm. GTP-bound tubulin subunits form αβ-heterodimers for microtubule assembly. These core building blocks interact longitudinally, polymerizing into protofilaments. The protofilaments then interact with one another through lateral bonding forces to form stable cylindrical microtubules. These cylindrical filaments are dynamic as they undergo repeated assembly and...


