InterPro domain: IPR022087

Proteins in this family include protein DA1 and its homologues. In Arabidopsis thaliana, DA1 is a ubiquitin-activated endopeptidase that limits final seed and organ size by restricting the period of cell proliferation [ 1 ]. DA1 is activated by the RING E3 ligases Big Brother and DA2, both of which are then inactivated by cleavage by the active peptidase. DA1 also cleaves and inactivates deubiquitinase UBP15 and transcription factors TCP15 and TCP22, all of which promote cell proliferation. Presence of an HEXXH motif, which when mutated leads to inactivity, suggests that DA1 is a metalloendopeptidase [ 2 ].

1. Control of final seed and organ size by the DA1 gene family in Arabidopsis thaliana. Genes Dev. 22, 1331-6
2. Ubiquitylation activates a peptidase that promotes cleavage and destabilization of its activating E3 ligases and diverse growth regulatory proteins to limit cell proliferation in Arabidopsis. Genes Dev. 31, 197-208