The invention describes isolated mTOR-associated proteins (“mTOR-APs”) as well as isolated variants and fragments thereof and the isolated nucleic acids encoding them. The invention also describes vectors and host cells containing nucleic acid encoding an mTOR-AP polypeptide and methods for producing an mTOR-AP polypeptide. Also described are methods for screening for compounds which modulate mTOR-AP activity and methods for treating or preventing a disorder that is responsive to mTOR-AP modulation.