UCLA researchers identified the Cullin-5 RING E3 ligase complex as a driver of T-cell exhaustion using a genome-wide CRISPR screen. In preclinical models, blocking this pathway helped engineered immune cells remain active longer and improved anti-solid tumor efficacy. The findings extend exhaustion biology beyond classic transcriptional controllers and point to ubiquitin-ligase regulation as a possible lever for boosting persistence. If validated across additional models and relevant translational biomarkers, the target could inform next-generation CAR-T and TCR strategies. For immunotherapy developers, the study provides a mechanistic rationale for combination regimens that address exhaustion while maintaining effector function in the tumor microenvironment.