The enzyme encoded by this gene is a multisubunit integral membrane protein of the endoplasmic reticulum that is composed of a catalytic subunit and transporters for glucose-6-phosphate, inorganic phosphate, and glucose. This gene is one of three glucose-6-phosphatase catalytic-subunit-encoding genes in mouse. Glucose-6-phosphatase catalyzes the hydrolysis of D-glucose 6-phosphate to D-glucose and orthophosphate and is a key enzyme in glucose homeostasis, functioning in gluconeogenesis and glycogenolysis. Mutations in this gene cause glycogen storage disease type I (GSD1).