The function of Ensembl gene identifier ENSG00000170262 (MRAP, melanocortin 2 receptor accessory protein) is as follows. Modulator of melanocortin receptors (MC1R, MC2R, MC3R, MC4R and MC5R). Acts by increasing ligand-sensitivity of melanocortin receptors and enhancing generation of cAMP by the receptors. Required both for MC2R trafficking to the cell surface of adrenal cells and for signaling in response to corticotropin (ACTH). May be involved in the intracellular trafficking pathways in adipocyte cells. {ECO:0000269|PubMed:15654338, ECO:0000269|PubMed:19329486, ECO:0000269|PubMed:20371771}.