RHEBL1 (Rheb-like 1) is a small GTPase that functions as a positive regulator of mTORC1 signaling and cellular growth pathways. As a member of the Ras superfamily, RHEBL1 binds GTP and exhibits intrinsic GTPase activity, localizing primarily to the cytoplasm 1. RHEBL1 activates mTORC1 through direct interaction with mTOR, with its membrane targeting conferred by C-terminal farnesylation being critical for this activation 2. Unlike its homolog Rheb1, RHEBL1 may modulate mTOR signaling through distinct mechanisms 3. Beyond mTOR, RHEBL1 activates NF-κB-mediated transcription 1 and binds to and activates AKT1, promoting keratin reorganization and cancer cell migration 4. RHEBL1 is downstream of the TSC1/TSC2 complex 5 and participates in exercise-induced mitochondrial biogenesis via the TAZ-regulated Rhebl1-mTOR axis 6. Clinically, RHEBL1 variants are associated with bipolar disorder risk in Han Chinese populations 7, and RHEBL1 expression is regulated by miR-138-5p in neuroprotection following hypoxic injury, suggesting therapeutic potential for ischemic stroke treatment 8.