Characterizing the Membrane Assembly of ASGPR Related to Mediated Endocytosis Using TriGalNAc-Probe-Based Super-Resolution Imaging

The asialoglycoprotein receptor (ASGPR) is a promising therapeutic target for drug delivery systems in hepatocellular carcinoma (HCC), exhibiting high affinity for specific carbohydrate residues and overexpression on malignant hepatic cells. However, their functional mechanisms remain poorly resolved at the single molecule level, hindering the rational optimization of ASGPR-targeted drug delivery systems. Here, we developed a trivalent <i>N</i>-acetylgalactosamine (TriGalNAc)-functionalized ligand probe leveraging high affinity to enable the nanoscale visualization of ASGPR organization and trafficking via super-resolution imaging. Fixed cell imaging revealed pronounced clustering patterns of the ASGPR on HCC membranes. In live cell experiments, we observed the distribution changes of residual ASGPR and returned ASGPR on the membrane during endocytosis, identifying protein clusters as key functional platforms for mediated ligand uptake. Additionally, comparisons with ligand probe binding under varying cell states confirmed that ASGPR aggregation degree correlates with its ligand-binding capacity. Strikingly, disruption of membrane carbohydrate cross-linking dispersed ASGPR clusters and attenuated ligand binding. These findings resolve the nanoscale assembly of ASGPR in HCC and unveil clustering-dependent ligand-binding regulation, advancing a fundamental understanding of ASGPR biology while providing new insights to refine receptor-targeted therapeutics.