E3 ubiquitin-protein ligase component of the CTLH complex. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Identified in the CTLH complex that contains at least RANBP9, MKLN1, MAEA, RMND5A, GID8 and ARMC8.