Structural highlights
Function
LGR4_XENTR Receptor for R-spondins that potentiates the canonical Wnt signaling pathway and is involved in the formation of various organs. Upon binding to R-spondins (RSPO1, RSPO2, RSPO3 or RSPO4), associates with phosphorylated LRP6 and frizzled receptors that are activated by extracellular Wnt receptors, triggering the canonical Wnt signaling pathway to increase expression of target genes. In contrast to classical G-protein coupled receptors, does not activate heterotrimeric G-proteins to transduce the signal. Its function as activator of the Wnt signaling pathway is required for the development of various organs, including liver, kidney, intestine, bone, reproductive tract and eye.
Publication Abstract from PubMed
The leucine-rich repeat-containing G-protein-coupled receptors (Lgrs) are a large membrane protein family mediating signaling events during development and in the adult organism. Type 2 Lgrs, including Lgr4, Lgr5, and Lgr6, play crucial roles in embryonic development and in several cancers. They also regulate adult stem cell maintenance via direct association with proteins in the Wnt signaling pathways, including Lrp5/6 and frizzled receptors. The R-spondins (Rspo) were recently identified as functional ligands for type 2 Lgrs and were shown to synergize with both canonical and noncanonical Wnt signaling pathways. We determined and report the structure of the Lgr4 ectodomain alone and bound to Rspo1. The structures reveal an extended horseshoe leucine-rich repeat (LRR) receptor architecture that binds, with its concave side, the ligand furin-like repeats via an intimate interface. The molecular details of ligand/receptor recognition provide insight into receptor activation and could serve as template for stem-cell-based regenerative therapeutics development.
Crystal Structures of Lgr4 and Its Complex with R-Spondin1.,Xu K, Xu Y, Rajashankar KR, Robev D, Nikolov DB Structure. 2013 Jul 23. pii: S0969-2126(13)00242-6. doi:, 10.1016/j.str.2013.07.001. PMID:23891289[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Xu K, Xu Y, Rajashankar KR, Robev D, Nikolov DB. Crystal Structures of Lgr4 and Its Complex with R-Spondin1. Structure. 2013 Jul 23. pii: S0969-2126(13)00242-6. doi:, 10.1016/j.str.2013.07.001. PMID:23891289 doi:10.1016/j.str.2013.07.001
