Orphan receptor. Could be involved in modulating differentiation and maintaining homeostasis of epithelial cells. This retinoic acid-inducible GPCR provides evidence for a possible interaction between retinoid and G-protein signaling pathways. Functions as a negative modulator of EGFR signaling (PubMed:25744720). Acts as a lung tumor suppressor (PubMed:18000218). Interacts (via its transmembrane domain) with EGFR (PubMed:25744720). Expressed predominantly in normal fetal and adult lung. Almost undetectable or expressed at very low levels in other tissues. By all-trans retinoic acid (ATRA). Phosphorylated in two conserved double-tyrosine motifs, TYR-318/TYR-321 and TYR-346/TYR-349 by EGFR. TYR-318 and TYR-321 are the preferred residues responsible for EGFR-mediated GPRC5A phosphorylation. Homozygous deficient mice developed more lung tumors during 1-2 years than heterozygous or wild-type mice. Belongs to the G-protein coupled receptor 3 family. Extended N-terminus.