Canonical Wnt receptor complex (Wnt-FZD-LRP complex)

The canonical Wnt receptor complex is a fundamental cell-surface signaling assembly that initiates the beta-catenin-dependent Wnt signaling pathway. It is primarily composed of a member of the Frizzled (FZD) family of seven-transmembrane receptors and a single-pass transmembrane co-receptor, typically Low-density lipoprotein receptor-related protein 5 (LRP5) or 6 (LRP6). Upon the binding of a canonical Wnt ligand, the complex undergoes conformational changes and phosphorylation that lead to the recruitment of intracellular proteins like Dishevelled and the Axin-based destruction complex to the plasma membrane. This recruitment prevents the proteasomal degradation of cytoplasmic beta-catenin, allowing it to accumulate and translocate into the nucleus, where it activates the transcription of genes essential for cell growth, differentiation, and the maintenance of stem cell niches. Dysregulation of this complex, through overexpression or mutations, is a key driver in various malignancies, including colorectal, breast, and liver cancers, as well as bone density disorders such as osteoporosis. Therapeutic strategies targeting the complex include monoclonal antibodies that block ligand binding and decoy receptors that sequester Wnt proteins, though clinical development is often challenged by toxicities related to the pathway's critical role in normal tissue regeneration.

Other names

Frizzled-LRP5/6 receptor complexWnt-Frizzled-LRP5/6 trimeric complexWnt receptor complexCanonical Wnt signalosomeFZD-LRP5/6 complex

Competitive inhibition of Wnt ligand binding to Frizzled and LRP5/6 receptors; sequestration of Wnt ligands via decoy receptors; and modulation of receptor turnover and stability on the cell surface.