Pho86p is an ER protein which is produced in response to phosphate starvation. It is essential for growth when phosphate levels are limiting. Pho86p is also involved in the regulation of Pho84p, a high-affinity phosphate transporter which is localized to the endoplasmic reticulum (ER) in low phosphate medium. When the level of phosphate increases Pho84p is transported to the vacuole. Pho86p is required for packaging of Pho84p in to COPII vesicles.