Low-density lipoprotein receptor-related protein 5 (LRP5) is a single-pass type I membrane protein with EGF-like and LDLR domains in the extracellular domain. LRP5 and LRP6 act as coreceptors with Frizzled for Wnt. The complex of Wnt-Fzd-LRP5-LRP6 triggers beta-catenin signaling through inducing aggregation of receptor-ligand complexes into ribosome-sized signalsomes. LRP5 plays a key role in skeletal homeostasis and many bone density related diseases are caused by mutations in LRP5 gene.
