Related Experiment Video
Updated: Jul 2, 2025
![Dynamic Imaging of Chimeric Antigen Receptor T Cells with [18F]Tetrafluoroborate Positron Emission Tomography/Computed Tomography](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F62334.jpg&w=3840&q=50)
Dynamic Imaging of Chimeric Antigen Receptor T Cells with [18F]Tetrafluoroborate Positron Emission Tomography/Computed Tomography
Published on: February 17, 2022
Degron-based bioPROTACs for controlling signaling in CAR T cells
Matthew S Kim1, Hersh K Bhargava2, Gavin E Shavey3
1Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA; Cell Design Institute, University of California, San Francisco, San Francisco, CA.
Abstract:
Chimeric antigen receptor (CAR) T cells have made a tremendous impact in the clinic, but potent signaling through the CAR can be detrimental to treatment safety and efficacy. The use of protein degradation to control CAR signaling can address these issues in pre-clinical models. Existing strategies for regulating CAR stability rely on small molecules to induce systemic degradation. In contrast to small molecule regulation, genetic circuits offer a more precise method to control CAR signaling in an autonomous, cell-by-cell fashion. Here, we describe a programmable protein degradation tool that adopts the framework of bioPROTACs, heterobifunctional proteins that are composed of a target recognition domain fused to a domain that recruits the endogenous ubiquitin proteasome system. We develop novel bioPROTACs that utilize a compact four residue degron and demonstrate degradation of cytosolic and membrane protein targets using either a nanobody or synthetic leucine zipper as a protein binder. Our bioPROTACs exhibit potent degradation of CARs and can inhibit CAR signaling in primary human T cells. We demonstrate the utility of our bioPROTACs by constructing a genetic circuit to degrade the tyrosine kinase ZAP70 in response to recognition of a specific membrane-bound antigen. This circuit is able to disrupt CAR T cell signaling only in the presence of a specific cell population. These results suggest that bioPROTACs are a powerful tool for expanding the cell engineering toolbox for CAR T cells.
Insights
Researchers developed bioPROTACs, a programmable protein degradation tool, to precisely control Chimeric Antigen Receptor (CAR) T cell signaling. This innovation enhances CAR T cell therapy safety and efficacy by enabling targeted degradation of CARs and associated signaling proteins.
Area of Science:
- Immunology and Molecular Biology: Focuses on cellular engineering and protein degradation mechanisms for advanced immunotherapy.
Background:
- Chimeric antigen receptor (CAR) T cell therapy shows promise but faces challenges with potent signaling impacting safety and efficacy.
- Current methods for regulating CAR signaling often rely on systemic small molecule degradation, lacking precise control.
- Genetic circuits offer autonomous, cell-by-cell regulation, presenting a more refined approach to controlling CAR activity.
Approach:
- Developed novel bioPROTACs, heterobifunctional proteins that link target recognition domains with ubiquitin proteasome system recruiters.
- Utilized a compact four-residue degron and demonstrated degradation of both cytosolic and membrane proteins using nanobodies or synthetic leucine zippers.
- Engineered a genetic circuit to degrade the tyrosine kinase ZAP70 specifically upon recognition of a target antigen, disrupting CAR T cell signaling conditionally.
Key Points:
- Demonstrated potent degradation of CARs and inhibition of CAR T cell signaling in primary human T cells using bioPROTACs.
- Successfully engineered a genetic circuit for antigen-specific, conditional degradation of ZAP70, thereby controlling CAR T cell activity.
- BioPROTACs offer a programmable protein degradation tool for precise, cell-autonomous regulation of CAR signaling.
Conclusions:
- BioPROTACs provide a powerful new tool for enhancing the safety and efficacy of CAR T cell therapies.
- This technology enables sophisticated cell engineering strategies for fine-tuning CAR T cell responses in a targeted manner.
- The development expands the toolbox for engineering CAR T cells, paving the way for more controlled and effective immunotherapies.
