Design and engineering of light-controlled cadherin

1134127 kortemmeintellectual优点。这个生物医学工程项目旨在创造新的钙粘蛋白分子，其功能可以和光可逆地切换（licad）。钙粘蛋白是主要的细胞-细胞粘附蛋白家族之一，在后生动物中通过在细胞连接处形成多聚体介导细胞间接触。可切换的licad将改进研究细胞粘附及其与细胞信号传导和组织发育的相互作用的方法。光控制还将为生物医学工程应用提供一种新的机制来操纵粘附。为了实现这些目标，研究人员提出在钙粘蛋白分子中计算设计的位置上，通过对半胱氨酸残基的工程配对来创建licad，将这些半胱氨酸与基于偶氮苯的、可光异构的发色团连接起来，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的功能。智力优势在于生命科学和工程原理在两个领域的创新整合：(i)基于光的方法来调节细胞-细胞粘附，提高空间和时间分辨率（现有的基于偶氮苯的技术的新应用），以及（ii）设计一种新的光控蛋白质构象开关的工程方法。这项研究成功完成的产品，验证了licad，将代表着通过工程设计和表征蛋白质开关来探测复杂细胞功能的结构设计的巨大进步。更广泛的影响。迫切需要新的工具来实时、高空间分辨率地表征和控制关键的生物过程。该项目旨在设计和验证这样一种工具，LiCads，以控制细胞-细胞相互作用。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、伤口愈合和肿瘤侵袭等方面的重要性，licad有望对基础生物学和疾病生物学的许多问题产生相当大的影响。三维细胞装配控制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很有用。研究生、本科生和高中阶段的学生将参与这项研究，以指导学生的记录为基础，以及与加州大学旧金山分校本科生暑期研究项目和旧金山联合学区的现有合作伙伴关系；这些项目强调在科学和工程领域未被充分代表的群体的参与。这项资助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.