E3 ubiquitin ligase catalyzing the covalent attachment of ubiquitin moieties onto substrate proteins (By similarity). Promotes the polyubiquitination and proteasome-dependent degradation of RELA/p65, thereby suppressing RELA-mediated NF-kappaB transactivation and negatively regulating inflammatory responses (By similarity). Plays a role in the regulation of spermiation and in male fertility (By similarity). . This is the function of ENSG00000075975 (MKRN2, makorin ring finger protein 2).