The function of ENSG00000172938 (MRGPRD, MAS related GPR family member D) is as follows. G protein-coupled receptor that acts as a mediator of peripheral pain and itch sensations (PubMed:15037633, PubMed:23091359, PubMed:35840655, PubMed:39580805). Activated by various ligands, such as beta-alanine, beta-aminoisobutyrate, angiotensin 1-7, alamandine and allantoin, causing a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of downstream effectors (PubMed:15037633, PubMed:23091359, PubMed:35840655, PubMed:39580805). MRGPRD is both coupled to G(q) and G(i) G proteins: G(q) coupling activates phospholipase C-beta, releasing diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3) second messengers, while G(i) coupling mediates inhibition of adenylate cyclase activity (PubMed:15037633, PubMed:23091359, PubMed:35840655, PubMed:39580805). MRGPRD is specifically expressed in neurons that innervate the epidermis and acts as a key mediator of skin stimuli, such as itch, pain and mechanical stimuli (By similarity). Required to maintain skin homeostasis in response to irritant dermatitis by initiating a signaling that promotes glutamate release, inhibiting mast cell hyperresponsiveness and skin inflammation (By similarity). Required to prevent cardiomyocyte hypertrophy following activation by alamandine, a decarboxylation product of angiotensin 1-7 (By similarity). Acts as a receptor for allantoin in dorsal root ganglion neurons, eliciting chronic itch (pruritus) (By similarity). {ECO:0000250|UniProtKB:Q91ZB8, ECO:0000269|PubMed:15037633, ECO:0000269|PubMed:23091359, ECO:0000269|PubMed:35840655, ECO:0000269|PubMed:39580805}.