E3 ubiquitin protein ligase MARCH4, RNF174, KIAA1399, MARCH 4, MARCH IV, Membrane associated RING CH protein IV, Membrane associated ring finger C3HC4 4, Membrane associated RING finger protein 4, mKIAA1399, RING finger protein 174, MARH4_HUMAN.
MARCH4, an E3 ubiquitin protein ligase, may mediate ubiquitination of MHC I and CD4, and promote their subsequent endocytosis and sorting to lysosomes via multivesicular bodies. E3 ubiquitin protein ligases accept ubiquitin from an E2 ubiquitin conjugating enzyme in the form of a thioester and then directly transfer the ubiquitin to targeted substrates.