Fig. 1

Structures of low-density lipoprotein receptor-related protein 1 (LRP1) and very low-density lipoprotein receptor (VLDLR). This Figure is modified from Figure 1 of a review written by Herz et al. [2]. The large extracellular ligand-binding subunit of LRP1 consists of 4 different ligand-binging clusters that contain 2, 8, 10, and 11 cysteine-rich ligand-binding repeats, respectively (red dots). Each cluster contains 1–4 epidermal growth factor (EGF) precursor homology domains, which include 2 cysteine-rich EGF repeats (blue circles) and 6 YWTD domains (blue lines). The cytoplasmic tail of LRP1 contains 2 NPXY motifs (marked with an asterisk). In addition, the cytoplasmic tail of LRP1 has 1 YXXL motif. Compared with LRP1, VLDLR is smaller. In addition, the O-linked sugar domain of VLDLR is enriched with serine and threonine residues (blue hexagon). Moreover, the cytoplasmic tail of VLDLR contains only 1 NPXY motif. Thus, the structure of LRP1 determines the endocytosis of ligands