TOR complex 2: a signaling pathway of its own.

Research on TOR has grown exponentially during the last decade, generating a complex model of the TOR signaling network. Rapamycin treatment provides a simple and straightforward method to inhibit the TOR signaling pathway and to study the influence of TOR on multiple cellular processes. The discovery of two distinct TOR complexes, TORC1 and TORC2, showed that studies using rapamycin targeted only one TOR signaling branch. TORC1 is directly inhibited by rapamycin, whereas TORC2 is not. There is no known TORC2-specific inhibitor, so genetic manipulation is required to study its biological function(s). Many studies in genetically tractable model organisms have expanded our understanding of TORC2 signaling. Here we focus on the TORC2 signaling pathway as revealed by these (mostly recent) studies.