Possesses E3 ubiquitin-protein ligase activity in vitro when associated with the E2 enzyme UBC8 in vitro (PubMed:20884812, PubMed:15644464). Plays combinatory roles with AIRP2 in the positive regulation of the abscisic acid-mediated drought stress response (PubMed:20884812). 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. Induced by salt stress, cold stress, drought stress and abscisic acid (ABA). The RING-type zinc finger domain is required for E3 ligase activity. No visible phenotype under normal growth conditions, but mutant seeds are insensitive to germination inhibition by abscisic acid (ABA). Plants over-expressing AIRP1 exhibit tolerance to severe drought stress.