Provide a mechanistic link between auxin and plasma membrane H(+)-ATPases (PM H(+)-ATPases, e.g. AHA1 and AHA2), and triggers PM H(+)-ATPases activity by promoting phosphorylation of their C-terminal autoinhibitory domain as a result of PP2C-D subfamily of type 2C phosphatases inhibition, thus leading to the acidification of the apoplast and the facilitation of solutes and water uptake to drive cell expansion (By similarity). Functions as positive effectors of cell expansion through modulation of auxin transport (By similarity). Involved in thermo-responsiveness of plant architecture (PubMed:31127632). Enhances plasma membrane H(+)-ATPase (PubMed:31127632). Probably involved in light intensity mediated root development (PubMed:31325959). Interacts with PP2C-D1. Higher expression in thermo-responsive cultivars (e.g. cv. Alst-1, cv. Ang-0 and cv. Com-0) than in low thermo-responsive cultivars (e.g. cv. Dja-1, cv. El-0 and cv. Kon). PIF4-dependent regulation by temperature (PubMed:31127632). In low thermo-responsive cultivars (e.g. Col-0), higher expression at 28 degrees Celsius than at 22 degrees Celsius in petioles but not in leaf blades (PubMed:31127632). In high thermo-responsive cultivars (e.g. cv. Alst-1 and cv. Ang-0) higher expression at 28 degrees Celsius than at 22 degrees Celsius in both petioles and leaf blades (PubMed:31127632). Induced by light (PubMed:31325959). Reduced rosette weight and area at 22 degrees Celsius but not at 28 degrees Celsius. Exhibits a high natural sequence polymorphism between cultivars, thus confering thermo-adaptation to environmental conditions. Belongs to the ARG7 family.