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Lysosome Targeting Chimeras (LYTACs) That Engage a Liver-Specific Asialoglycoprotein Receptor for Targeted Protein Degradation

submitted on 30.07.2020, 06:06 and posted on 30.07.2020, 11:57 by Green Ahn, Steven Banik, Caitlyn L. Miller, Nicholas Riley, Jennifer R. Cochran, Carolyn Bertozzi

Selective protein degradation platforms have afforded new development opportunities for therapeutics and tools for biological inquiry. The first lysosome targeting chimeras (LYTACs) targeted extracellular and membrane proteins for degradation by bridging a target protein to an endogenous lysosome targeting receptor, the cation-independent mannose-6-phosphate receptor (CI-M6PR). Here we developed LYTACs that engage the asialoglycoprotein receptor (ASGPR), a liver-specific lysosomal targeting receptor, to degrade membrane proteins in a tissue-specific manner. We conjugated antibody-based binders targeting cell-surface proteins to a tri-GalNAc motif that engages ASGPR. The resulting LYTACs directed lysosome trafficking of the bound targets and subsequent degradation. Degradation mediated by an EGFR-targeted GalNAc-LYTAC resulted in significant functional effects on the downstream kinase signaling of EGFR compared to canonical inhibition with a monoclonal antibody. Furthermore, we demonstrated that a small target binder, a 3.4 kDa peptide, can be linked to a single tri-GalNAc ligand to degrade integrins and significantly reduce cell proliferation. Site-specific chemical conjugation of one or two tri-GalNAc ligands to antibody scaffolds improved the pharmacokinetic profile of GalNAc-LYTACs in vivo compared to non-specific chemical conjugation. GalNAc-LYTACs represent an exciting new paradigm for cell-type restricted degradation of proteins.


Email Address of Submitting Author


Stanford University


United States

ORCID For Submitting Author


Declaration of Conflict of Interest

G.A., S.M.B., and C.R.B. are included as co-inventors on a patent application relating to lysosome targeting chimeras owned by Stanford University. C.R.B. is a co-founder and Scientific Advisory Board member of Palleon Pharmaceuticals, Enable Bioscience, Redwood Biosciences (a subsidiary of Catalent), InterVenn Biosciences, and Lycia Therapeutics, and a member of the Board of Directors of Eli Lilly & Company. J.R.C. is a founder of xCella Biosciences and Combangio Inc. and co-founder and director of Trapeze Therapeutics.