Related Experiment Video
Updated: Jun 21, 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 Kim1,2,3, Hersh K Bhargava2,3,4, Gavin E Shavey2
1Tetrad Graduate Program, University of California San Francisco, San Francisco, California 94158, United States.
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 preclinical 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 can disrupt CAR T cell signaling only in the presence of a specific cell population. These results suggest that bioPROTACs are powerful tools for expanding the CAR T cell engineering toolbox.
Insights
Researchers developed bioPROTACs, a novel protein degradation tool, to precisely control chimeric antigen receptor (CAR) T cell signaling. This technology enhances CAR T cell therapy safety and efficacy by enabling cell-specific degradation of CARs.
Area of Science:
- Immunology
- Molecular Biology
- Biotechnology
Background:
- Chimeric antigen receptor (CAR) T cells offer potent cancer therapy but face challenges with signaling control, impacting safety and efficacy.
- Current methods for regulating CAR stability often rely on systemic small molecules, limiting precision.
- Genetic circuits present an alternative for autonomous, cell-by-cell control of CAR signaling.
Purpose of the Study:
- To develop a programmable protein degradation tool for precise control of CAR T cell signaling.
- To engineer novel bioPROTACs capable of targeting CARs and other proteins for degradation.
- To demonstrate the utility of bioPROTACs in a genetic circuit for antigen-specific CAR T cell inhibition.
Main Methods:
- Designed and synthesized novel bioPROTACs utilizing a compact four-residue degron.
- Employed nanobodies or synthetic leucine zippers as protein binders for target recognition.
- Tested bioPROTACs for degradation of cytosolic and membrane proteins, including CARs, in primary human T cells.
- Constructed a genetic circuit for antigen-specific degradation of ZAP70 kinase.
Main Results:
- Successfully demonstrated potent degradation of CARs and inhibition of CAR T cell signaling.
- Validated bioPROTACs for targeting both cytosolic and membrane proteins.
- Engineered a genetic circuit that specifically degrades ZAP70 upon antigen recognition, disrupting CAR T cell activity only in target cell populations.
- Showcased bioPROTACs as a versatile tool for CAR T cell engineering.
Conclusions:
- BioPROTACs offer a precise and programmable method for controlling CAR T cell signaling, overcoming limitations of current strategies.
- This technology enhances the safety and efficacy of CAR T cell therapies by enabling autonomous, cell-specific regulation.
- BioPROTACs significantly expand the engineering toolbox for developing advanced CAR T cell therapeutics.
