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). 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). Accumulates in response to sirtinol (a small molecule that activates many auxin-inducible genes and responses) and auxin (PubMed:12893885, PubMed:16006581). Expressed in the dark (PubMed:16412086). 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). 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.