The mammalian target of rapamycin, mTOR, is a key node in cellular regulation: its dysregulation is important in a number of disease states, including various cancers. A recent study identifies a new partner and regulator of mTOR, which can alter the balance of signaling downstream of mTOR and appears to be important in certain cancers, such as multiple myelomas. © The Author (2009). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS.All rights reserved.