Rheb also known as RHEB2 is a member of the small GTPase superfamily. Rheb plays a crucial role in cellular signaling pathways, particularly in the regulation of mTOR (mechanistic target of rapamycin) signaling, which is vital for cell growth, proliferation, and survival. Rheb is primarily located in the cytoplasm and can translocate to the lysosome, where Rheb interacts with mTORC1 (mTOR complex 1) to promote anabolic processes. This localization is significant because Rheb integrates signals from growth factors and nutrient availability, thereby influencing cellular metabolism and growth. Dysregulation of Rheb and associated signaling pathways has been implicated in various cancers and metabolic disorders, making Rheb an important target for therapeutic intervention.