The function of ENSG00000102858 (MGRN1, mahogunin ring finger 1) is as follows. E3 ubiquitin-protein ligase. Mediates monoubiquitination at multiple sites of TSG101 in the presence of UBE2D1, but not of UBE2G1, nor UBE2H (PubMed:17229889, PubMed:19703557). Plays a role in the regulation of endosome-to-lysosome trafficking (PubMed:17229889). Impairs MC1R- and MC4R-signaling by competing with GNAS-binding to MCRs and inhibiting agonist-induced cAMP production (PubMed:19737927). Does not inhibit ADRB2-signaling (PubMed:19737927). Does not promote MC1R ubiquitination (PubMed:19737927). Acts also as a negative regulator of hedgehog signaling (By similarity). {ECO:0000250|UniProtKB:Q9D074, ECO:0000269|PubMed:17229889, ECO:0000269|PubMed:19703557, ECO:0000269|PubMed:19737927}.