Aux/IAA proteins are short-lived transcriptional factors that function as repressors of early auxin response genes at low auxin concentrations. Repression is thought to result from the interaction with auxin response factors (ARFs), proteins that bind to the auxin-responsive promoter element (AuxRE). Formation of heterodimers with ARF proteins may alter their ability to modulate early auxin response genes expression. Homodimers and heterodimers. By auxin. The N-terminal half of the protein contains the conserved domain II which is required for the correct degradation of the protein through the SCF-mediated ubiquitin-proteasome pathway. Interactions between Aux/IAA proteins and auxin response factors (ARFs) occur through their C-terminal dimerization domains III and IV. Lacks the EAR-like motif (Domain I) which is one of the conserved features of the Aux/IAA family. Belongs to the Aux/IAA family.