Design and engineering of light-controlled cadherin

1134127科顿智慧功绩。这个生物医学工程项目旨在创造新的钙粘附素分子，其功能可以用光(LiCad)进行可逆切换。钙粘附素是主要的细胞-细胞黏附蛋白家族之一，通过在细胞连接处形成多聚体来调节后生动物的细胞间接触。可切换的LiCad将使研究细胞黏附及其与细胞信号和组织发育的相互作用的方法得到改进。光控制还将提供一种新的机制来操纵生物医学工程应用中的粘附性。为了实现这些目标，有人建议通过在钙粘蛋白分子中计算设计的位置上工程半胱氨酸残基对来创建LiCad，将这些半胱氨酸与基于偶氮苯的可光异构化的发色团连接起来，并通过发色团的光异构化来触发钙粘附素构象的变化来切换钙粘附素的功能。其智力优势在于将生命科学和工程学原理结合起来，在两个领域进行创新：(I)基于光的方法，通过提高空间和时间分辨率来调节细胞与细胞的黏附(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，将代表着通过工程和表征蛋白质开关来设计结构的相当大的进步，这种开关有助于探索复杂的细胞功能。迫切需要新的工具来实时、高空间分辨率地描述和控制关键的生物过程。该项目旨在设计和验证这样一个工具LiCads，以控制细胞与细胞之间的相互作用。由于钙粘附素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、肿瘤的创伤愈合和肿瘤侵袭中的重要性，LiCad有望对基础生物学和疾病生物学中的许多问题产生重大影响。在三维上控制细胞组装也是复杂细胞工程应用的关键要求。因此，LiCad对生物学家和生物工程师都应该是有用的。研究生、本科生和高中学生将参与这项研究，建立在指导学生的记录基础上，并建立与加州大学旧金山分校本科生暑期研究计划和旧金山联合学区的现有合作伙伴关系；这些计划强调在科学和工程领域代表性不足的群体的参与。这项资助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.