TogoPhosTAC: A Ready-To-Go and Adaptable Targeted Protein Dephosphorylation System

Phosphorylation targeting chimeras (PhosTACs) recruit phosphatases to dephosphorylate target proteins by proximity-induced protein interactions. However, recruiting a phosphatase subunit or holoenzyme using small molecules without compromising its activity or adversely disturbing its cellular function remains challenging. In addition, many phosphatases do not have a favorable activator or binder currently. To overcome these limitations, here, we report an adapted mode of action, named togoPhosTAC, based on the small molecule PhosTAC, an engineered fusion FKBP12 ^(F36V) -phosphatase, and a lipid-based delivery system for targeted protein dephosphorylation. Through lipid-based nanoparticles, we delivered the pre-fused complex of PhosTACs and FKBP12 ^(F36V) -phosphatases or in mRNA format directly for rapid and efficient targeted intracellular protein dephosphorylation. The togoPhosTAC was able to dephosphorylate epidermal growth factor receptor (EGFR), tau, and α-synuclein. Furthermore, togoPhosTAC-mediated tau dephosphorylation also correlates with reduced aggregation. In sum, our hybrid small molecules and biologic adaptor strategy bypassed the challenges of phosphatase ligand development and provided an alternative and generalizable solution for precise modulation of targeted protein in cellulo .