This gene is a homolog of Arabidopsis thaliana WALL ARE THIN 1 (WAT1), and Medicago truncatula NODULIN 21 (MtN21). It encodes for a integral membrane protein that faciliates auxin effux from vacuole, and belongs to a family of plant drug/metabolite exporter (P-DME) proteins. It is known to be ubiquitiously expressed in plants but specifically in vascular tissues and regulates secondary cell wall thickening and cell elongation. Protein is localized to the vacuolar memebrane (tonoplast).