Functional Structural Biology of Noncollagenous Bone Matrix Proteins

骨是一种复杂的无机-有机复合材料，具有重要的力学和生理意义。尽管是次要成分，但非胶原基质蛋白（NCP）发挥调节作用，并赋予钙化有机基质凝聚力。虽然转基因小鼠模型和细胞培养研究在理解NCP的整体生物活性及其对构建和维持骨骼的贡献方面取得了实质性进展，但其分子结构如何介导矿物质沉积仍然是争论的主题。目前的大部分信息来自计算机预测和人工试管分析。虽然信息量很大，但这种关于蛋白质-矿物质关系的实验和理论研究充其量只是在分子尺度上在人体复杂的生物环境中真正发生的事情的“粗略近似”。因此，需要在更生理相关的条件下验证此类研究的结果。为了实现这一目标，本提案将利用综合功能结构生物学的方法来理解分子结构、基序和结构域如何定义NCP与矿物相的关系。该实验室一直专注于一种称为骨唾液酸蛋白（BSP）的NCP，因为它与初始矿化事件有关。我们已经获得了新的数据，这NCP，不能预测从目前的知识，具有重要的功能的影响。我们的短期目标是使用基本结构生物学方法，分子修饰，细胞培养和实验操作的组合来全面了解BSP分子的功能结构域，这将考虑到身体的生理学，并解决计算机预测和人工试管测定的局限性。利用BSP获得的知识，从长远来看，我们打算将我们的研究扩展到其他骨NCP，以全面了解该蛋白质家族如何在矿物质沉积期间调节基本的细胞和基质事件。该研究计划将为高素质的人员（HQP学生和技术培训生）提供独特的培训环境，基于分子和结构生物学，仅在世界各地的少数实验室提供。该培训不仅适用于骨生物学，而且适用于广泛的基础生物学问题。它还将提供一组蛋白质的分子结构-功能关系所需的基本信息，这些蛋白质在骨和硬组织的基础生物学中发挥重要作用，从而有助于我们理解四足动物生物学中的关键组织。

Bone is a complex inorganic-organic composite with critical mechanical and physiological implications. Despite being minor components, noncollagenous matrix proteins (NCPs) play regulatory roles and impart cohesion to the calcified organic matrix. While transgenic mouse models and cell culture studies have allowed substantial progress in understanding the overall biological activity of NCPs and their contribution to building and maintaining bone, how their molecular structure mediates mineral deposition is still subject of debate. Much of the current information derives from in silico predictions and artificial test tube assays. While extremely informative, such experimental and theoretical studies on protein-mineral relationships are at best “crude approximations” of what really happens at the molecular scale in the complex biological environment of the body. There is therefore a need to validate results from such studies under more physiologically- relevant conditions. Towards this objective, this proposal will exploit an integrative functional structural biology' approach to understand how molecular structure, motifs and domains define the relationship of NCPs to the mineral phase.******The laboratory has been focusing on a NCP called bone sialoprotein (BSP) because it is associated with initial mineralization events. We have obtained novel data on this NCP that could not have been predicted from current knowledge and that have important functional implications. Our short-term objective is to obtain a comprehensive understanding of the functional domains of the BSP molecule using a combination of basic structural biology approaches, molecular modifications, cell culture and experimental manipulations, which will take into account the physiology of the body and address the limitations of in silico predictions and artificial test tube assays. Taking advantage of the knowledge acquired for BSP, in the longer term we intend to extend our studies to the other bone NCPs in order to obtain a comprehensive understanding of how this family of proteins regulates basic cellular and matrix events during mineral deposition.******This research program will provide highly qualified personnel (HQP both students and technical trainees) with a unique training environment, based on molecular and structural biology, only available in few laboratories throughout the world. This training will not only be applicable to bone biology but also to a broad range of fundamental biological questions. It will also provide needed fundamental information on molecular structure-function relationships of a group of proteins that play important roles in the basic biology of bone and hard tissues, in general, thereby contributing to our understanding of a critical tissue in tetrapod biology.