Microtubule bundles in the mitotic spindle: probing how mechanical and functional robustness emerge from molecular architecture

有丝分裂纺锤体中的微管束：探讨分子结构如何产生机械和功能稳健性

• 批准号: 10028927
• 负责人: Mary Williard Elting
• 金额: $ 36.6万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10028927
• 关键词: Address; Affect; Architecture; Axon; Biochemistry; Biological Process; Building Codes; Bundling; Cell division; Cells; Chromosome Segregation; Chromosomes; Cilia; Congenital Abnormality; Coupling; Crosslinker; Disease; Engineering; Ensure; Equilibrium; Fiber; Fission Yeast; Goals; In Vitro; Kinetochores; Lead; Malignant Neoplasms; Maps; Measures; Mechanics; Microtubule Bundle; Microtubules; Mitotic spindle; Molecular; Molecular Probes; Morphology; Property; Spontaneous abortion; Stereotyping; Structure; Sum; Time; Work; base; daughter cell; flexibility; genetic information; in vivo; insight; mechanical properties; molecular scale; novel; programs; reconstitution; response; tool; transmission process

Project Summary/Abstract The mitotic spindle is a microtubule-based machine that segregates chromosomes into two new daughter cells when cells divide. Accurate spindle function is critical: mistakes lead to extra or missing chromosomes, which are associated with cancer, birth defects, and miscarriage. Spindle function requires robust coupling of biochemistry and mechanics. Yet, understanding how this self-organizing machine generates the required forces in the right place at the right time remains a challenge. Our long term goal is to determine how micron-scale mechanical properties of the spindle emerge from molecular-scale biochemistry. We focus on microtubule bundles, which provide organization and underpin rigidity in the spindle and in other microtubule-based structures. We do not understand what material properties bundling molecules impart to spindle bundles, how their molecular properties allow them to do so, or how these emergent mechanical properties are tuned for biological functions. To address these questions, we will measure quantitative readouts of how bundles respond to perturbations that alter mechanics. We take a multi-system approach to understanding bundle mechanics in mammalian kinetochore-fibers (k-fibers), which attach and segregate chromosomes; in fission yeast S. pombe spindles, whose stereotyped organization facilitates probing how specific crosslinker properties affect bundles overall; and in vitro, where we have more precise control. Our approach is organized into two programs: (1) probing the molecular and mechanical organization of spindle microtubule bundles, and (2) controlling spindle microtubule bundles to alter function through novel mechanics. In Program 1, we will determine how k-fiber organization balances competing mechanical constraints of robust force-transmission for chromosome segregation with flexibility to adapt to changing spindle morphology. We will also develop new tools to measure force between microtubules within spindle bundles, determining how these bundles effectively transmit force to achieve their mechanical functions. In Program 2, we will determine how the geometric and mechanical properties of microtubule crosslinkers impart bundle-scale properties that are adapted to particular functions. We will create engineered crosslinkers whose mechanical and geometric properties we will control, and use them to build reconstituted microtubule bundles in vitro, and to alter bundle properties in vivo. By measuring the response of these bundles to molecular-scale changes, we will determine how micron-scale properties emerge. In sum, the proposed work will map how molecular scale parts impart spindle bundles with properties that balance competing mechanical constraints. In the long term, this approach may lead to new insight into how altering the cell’s “building code” can be harnessed to target microtubule architectures with key roles in disease, or to build novel architectures. This approach can extend to understand the emergent mechanics of microtubule bundle architectures beyond the spindle, such as in cilia and axons.

项目总结/摘要 有丝分裂纺锤体是一种基于微管的机器，它将染色体分离成两个新的染色体。 细胞分裂时的子细胞。准确的主轴功能至关重要：错误导致多余或缺失 染色体，这与癌症，出生缺陷和流产有关。主轴功能要求 生物化学和力学的强大耦合。然而，了解这个自组织机器 在适当的时间和适当的地点组建所需的部队仍然是一个挑战。我们的长期目标是 确定纺锤体的微米级机械特性是如何从分子级生物化学中产生的。 我们专注于微管束，它在纺锤体和其他细胞中提供组织和支撑刚性。 微管结构。我们不了解捆绑分子赋予的材料性质， 纺锤体束，它们的分子特性如何允许它们这样做，或者这些新兴的机械 属性被调整为生物功能。为了解决这些问题，我们将量化 光束对改变力学的扰动的反应。我们采用多系统方法， 理解哺乳动物的运动舞蹈纤维（k纤维）中的束力学， 染色体;裂殖酵母S. pombe纺锤体，其定型的组织有助于探索如何 具体的交联剂性能影响束整体;和在体外，我们有更精确的控制。 我们的方法分为两个程序：（1）探索分子和机械组织的 纺锤体微管束，和（2）通过新的方法控制纺锤体微管束改变功能 力学在方案1中，我们将确定k纤维组织如何平衡竞争机械 具有适应变化的灵活性的染色体分离的鲁棒力传递约束 纺锤体形态我们还将开发新的工具来测量纺锤体内微管之间的力 束，确定这些束如何有效地传递力，以实现其机械功能。在 程序2，我们将确定如何几何和机械性能的微管交联剂传授 适合特定功能的捆绑规模属性。我们将创造工程交联剂， 我们将控制机械和几何性质，并使用它们来构建重组的微管束 在体外，并在体内改变束特性。通过测量这些束对分子尺度的反应， 变化，我们将确定微米级特性如何出现。 总之，拟议的工作将映射分子尺度部分如何赋予纺锤体束特性 来平衡相互竞争的机械约束。从长远来看，这种方法可能会导致新的见解， 如何改变细胞的“建筑代码”可以利用目标微管结构的关键作用， 疾病，或者建造新的建筑。这种方法可以扩展到理解 微管束结构超出纺锤体，如纤毛和轴突。