Receptor for R-spondins that potentiates the canonical Wnt signaling pathway and acts as a marker of multipotent stem cells in the epidermis. 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. May act as a tumor suppressor.
