UC San Diego

Living organisms sense and respond to environmental temperature changes. The heat shock factors regulate the heat shock response to cope with the proteotoxic stress triggered by hyperthermia. It has been reported that abnormal heat shock factor activities are associated with multiple diseases, such as cancer and neurodegenerative diseases. Understanding the activation mechanism of heat shock factors can not only help the development of targeted treatment for those diseases, but also provide new opportunities for designing heat-responsive synthetic gene circuits. Besides heat shock factors, the extracellular matrix protein elastin forms liquid-liquid phase separations when the temperature is high. Elastin-like proteins have been broadly applied to tissue engineering and drug delivery attributed to their tunability and biocompatibility. Understanding the behavior of elastin-like proteins in live cells can extend its applications from in vitro to in vivo. In this dissertation, I first discussed the activation mechanism of the heat shock factor 1, specifically, the interaction patterns between two critical heptad repeat domains. Using this heat shock response, I engineered heat-inducible CAR T cells and showed promising anti-tumor efficacy in solid tumors. On the other hand, I tested the liquid-liquid phase separation property of elastin-like proteins in live cells. Based on the observations, I engineered a CRISPR-ELP droplet to label non-repetitive genomic loci. The dynamics of the DNA double-strand break repair process were studied using this CRISPR-ELP droplet. This dissertation systemically elaborates on the action mechanisms of two heat-sensitive proteins, the human heat shock factor 1 and the elastin-like proteins, and their applications in tumor immunotherapy and DNA damage studies.