Function
Receptor for abscisic acid (ABA) required for ABA-mediated responses such as stomatal closure and germination inhibition. Inhibits the activity of group-A protein phosphatases type 2C (PP2Cs) in an ABA-independent manner but more efficiently when activated by ABA. Confers enhanced sensitivity to ABA (PubMed:19407143, PubMed:19624469, PubMed:19769575, PubMed:19889877, PubMed:23844015, PubMed:21658606). Can be activated by both (-)-ABA and (+)-ABA (PubMed:23844015). Mediates crosstalk between ABA and auxin signaling to regulate lateral root growth. Required for lateral root growth suppression by ABA. In response to auxin, promotes lateral root growth by enhancing MYB77-dependent transcription of the auxin-responsive gene IAA19. Enhances the abilities of MYB44 and MYB73 to activate IAA19 gene (PubMed:24894996).