DEPTOR is an mTOR inhibitor whose expression is negatively regulated by mTOR. DEPTOR expression is required to maintain PI3K and Akt activation and to inhibit apoptosis. DEPTOR is expressed in different microvascular ECs (endothelial cells). It plays a key role in maintaining stem cell pluripotency by limiting mTOR activity in undifferentiated embryonic stem cells (ESCs). It is overexpressed in RPMI-8226 human multiple myeloma cells, and plays an important role in maintaining cell survival.