Tuberin is a product of the TSC2 tumor suppressor gene and an important regulator of cell proliferation and tumor development. Mutations in either TSC2 or the related TSC1 (hamartin) gene cause tuberous sclerosis complex (TSC), an autosomal dominant disorder characterized by development of multiple, widespread non-malignant tumors. Tuberin is directly phosphorylated at Thr1462 by Akt/PKB. Phosphorylation at Thr1462 and Tyr1571 regulates tuberin-hamartin complexes and tuberin activity.