Mediator of sterol homeostasis involved in sterol uptake, trafficking and distribution into membranes. Regulates also the sphingolipid metabolism. Restricted to tissues in which cells are actively dividing or expanding. Mostly expressed in roots and flowers, and, to a lower extent, in stems and leaves. In floral tissues, expressed in pollen grains and fertilized ovules until they develop into seeds, and, at low levels, in the styles. Observed in germinating seedlings, and later confined to shoot and root apical meristems. Accumulates in emerging leaves and in the vascular tissue of adult leaves. Belongs to the ARV1 family.