Design and engineering of light-controlled cadherin

1134127 KortemmeIntellectual Merit.这个生物医学工程项目旨在创造新的钙粘蛋白分子，其功能可以通过光可逆地切换（LiCads）。钙粘蛋白是一种主要的细胞间粘附蛋白家族，通过在细胞连接处形成多聚体介导后生动物的细胞间接触。可切换的LiCads将能够改进研究细胞粘附及其与细胞信号传导和组织发育相互作用的方法。光控制还将提供一种新的机制，以操纵生物医学工程应用中的粘附。为了实现这些目标，提出了通过在钙粘蛋白分子中计算设计的位置处工程化半胱氨酸残基对来创建LiCads，将这些半胱氨酸与基于偶氮苯的可光异构化的发色团桥接，并通过发色团的光异构化触发钙粘蛋白构象变化来切换钙粘蛋白功能。其智力价值在于将生命科学和工程学原理结合起来，用于两个领域的创新：（i）以光为基础的方法，以提高空间和时间分辨率来调节细胞-细胞粘附（现有偶氮苯技术的新应用），以及（ii）设计新的光控蛋白质构象开关的工程方法。成功完成这项研究的产品，经过验证的LiCads，将代表通过工程和表征蛋白质开关的结构设计的相当大的进步，可用于探测复杂的细胞功能。更广泛的影响。非常需要新的工具来表征和控制具有高空间分辨率的真实的时间的关键生物过程。该项目旨在设计和验证这样一种工具LiCads，以控制细胞间的相互作用。由于钙粘蛋白介导的相互作用在细胞生物学、组织形态发生、发育过程中的组织重塑、伤口愈合和癌症中的肿瘤侵袭中的重要性，可以预期LiCads对基础和疾病生物学中的许多问题具有相当大的影响。三维控制细胞组装也是复杂细胞工程应用的关键要求。因此，LiCads应该对生物学家和生物工程师都有用。在研究生，本科和高中水平的学生将参与这项研究，建立在辅导学生的跟踪记录，并与UCSF本科生暑期研究计划和旧金山弗朗西斯科联合学区现有的合作伙伴关系;这些计划强调在科学和工程中代表性不足的群体的参与。该补助金下的研究将与旨在促进生命科学和物理/工程科学学生之间合作的教育相结合。

1134127KortemmeIntellectual Merit. This biomedical engineering project aims to create new cadherin molecules whose function can be reversibly switched with light (LiCads). Cadherins comprise one of the major cell-cell adhesion protein families and mediate intercellular contacts in metazoans by forming multimers in cellular junctions. Switchable LiCads would enable improved ways to study cell adhesion and its interplay with cell signaling and tissue development. Light control would also provide a new mechanism to manipulate adhesion in biomedical engineering applications. To achieve these objectives, it is proposed to create LiCads via engineering pairs of cysteine residues at computationally designed locations in the cadherin molecule, bridge these cysteines with an azobenzene-based, photoisomerizable chromophore, and switch cadherin function by triggering cadherin conformational changes through photoisomerization of the chromophore. The intellectual merit lies in the integration of life science and engineering principles for innovation in two areas: (i) a light-based approach to modulate cell-cell adhesion with improved spatial and temporal resolution (a novel application of existing azobenzene-based technologies), and (ii) an engineering methodology to design a new light-controlled protein conformational switch. The product from successful completion of this research, validated LiCads, would represent a considerable advance in the design of structure by engineering and characterizing a protein switch useful to probe complex cellular functions.Broader Impact. There is great need for novel tools to characterize and control key biological processes in real time with high spatial resolution. This project aims to engineer and validate such a tool, LiCads, to control cell-cell interactions. Because of the importance of cadherin-mediated interactions in cell biology, tissue morphogenesis, tissue remodeling during development, wound healing and tumor invasiveness in cancer, LiCads can be expected to have considerable impact on many problems in basic and disease biology. Controlling cell assembly in three dimensions is also a key requirement of complex cellular engineering applications. Therefore, LiCads should be useful to both biologists and biological engineers. Students at the graduate, undergraduate and high school levels will participate in this research, building on a track record in mentoring students, and on existing partnerships with the UCSF Undergraduate Summer Research Program and the San Francisco Unified School District; these programs emphasize participation of groups underrepresented in science and engineering. Research under this grant will be integrated with education designed to foster collaboration between students from the life and physical/engineering sciences.