FLASH-AWAY: Intrabody-Directed Targeting of Optogenetic Tools for Protein Degradation

Protein homeostasis, or proteostasis, is essential for cellular proteins to function properly. The buildup of abnormal proteins (such as damaged, misfolded, or aggregated proteins) is associated with many diseases, including cancer. Therefore, maintaining proteostasis is critical for cellular health. Currently, genetic methods for modulating proteostasis, such as RNA interference and CRISPR knockout, lack spatial and temporal precision. They are also not suitable for depleting already-synthesized proteins. Similarly, molecular tools like PROTACs and molecular glue face challenges in drug design and discovery. To directly control targeted protein degradation within cells, we introduce an intrabody-based optogenetic toolbox named Flash-Away. Flash-Away integrates the light-responsive ubiquitination activity of the RING domain of TRIM21 for protein degradation, coupled with specific intrabodies for precise targeting. Upon exposure to blue light, Flash-Away enables rapid and targeted degradation of selected proteins. This versatility is demonstrated through successful application to diverse protein targets, including actin, MLKL, and ALFA-tag fused proteins. This innovative light-inducible protein degradation system offers a powerful approach to investigate the functions of specific proteins within physiological contexts. Moreover, Flash-Away presents potential opportunities for clinical translational research and precise medical interventions, advancing the prospects of precision medicine.