FK506-binding protein 12 F36V-tagged protein of interest (FKBP12(F36V)-POI)

The FKBP12F36V-tagged protein of interest is a synthetic substrate used in the degradation TAG (dTAG) system for rapid and reversible protein depletion. This system utilizes a mutant form of the FK506-binding protein 12 (FKBP12) containing a phenylalanine-to-valine substitution at residue 36, which creates a unique binding pocket for synthetic ligands (Nabet et al., 2018, Nature Chemical Biology). By fusing this tag to a protein of interest (POI) using CRISPR/Cas9 or transgene expression, researchers can target the POI for degradation using heterobifunctional dTAG molecules. These molecules recruit E3 ubiquitin ligases, such as Cereblon (CRBN) or Von Hippel-Lindau (VHL), to the tagged protein, inducing its ubiquitination and subsequent degradation by the 26S proteasome (Nabet et al., 2020, Nature Communications). This technology is primarily used for target validation in drug discovery, allowing for the study of the biological consequences of losing a specific protein's function in real-time. Unlike traditional genetic knockouts, the dTAG system provides temporal control and can distinguish between the scaffolding and enzymatic functions of a protein. The F36V mutation is critical as it allows the dTAG ligands to selectively bind the mutant tag over the endogenous, wild-type FKBP12 protein, minimizing off-target effects.

Other names

dTAG systemFKBP12 F36V fusion proteinFKBP12 mutant-tagged proteindegradation TAG

Recruitment of E3 ubiquitin ligases (e.g., CRBN or VHL) to the tagged protein via heterobifunctional small molecules (dTAG ligands), leading to polyubiquitination and subsequent proteasomal degradation.