Functions as a positive effector of cell expansion through modulation of auxin transport. By auxin (PubMed:8159792, PubMed:8612592, PubMed:9278170). Induced by epi-brassinolide (epi-BL) (PubMed:22961663). Induced by cycloheximide (PubMed:8159792). Belongs to the ARG7 family.