3.A.1.204.28
ABCG25 of 662 aas and 6 TMSs in a C-M domain arrangement.  Transports abscisic acid, ABA, a plant hormone that influences developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure (Lefèvre and Boutry 2018). Strigolactones promote the localisation of the ABA exporter ABCG25 at the plasma membrane in root epidermal cells of Arabidopsis thaliana (Russo et al. 2023).  Thus, a mechanism for ABA homeostasis regulation is proposed in the context of osmotic stress acclimation: the fine tuning by strigolactones of ABCG25 localisation in root cells (Russo et al. 2023).  The cryo-EM structure and molecular mechanism used by the abscisic acid transporter, ABCG25, which regulates stomatal closure, seed germination and development, has been described (Huang et al. 2023). It was solved in an inward-facing apo conformation, an ABA-bound pre-translocation conformation and an outward-facing occluded conformation. A 'gate-flipper' translocation model was proposed (Huang et al. 2023). The structural basis for abscisic acid efflux mediated by ABCG25 in Arabidopsis thaliana has been described (Ying et al. 2023; Huang et al. 2023).