Design and engineering of light-controlled cadherin

University Of California-San Francisco, San Francisco CA

Investigators

Abstract

1134127 Kortemme Intellectual 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.