Molecular Cell O e

assembly and maintenance of their active complexes. Neverthe-less, how this is achieved remains unclear.family (including ATM, ATR, DNA-PKcs, mTOR, SMG1, and TRRAP) raised the possibility that TEL2 affects such diverse cellular processes through its role as a universal regulator of essential for Pih1 stability and, therefore, for R2TP complex stabilization (Zhao et al., 2008). In mammalian cells, the R2TP complex has been shown to associate with prefoldin proteins,the PIKKs (Takai et al., 2007). Indeed, within this family, ATM, ATR, and DNA-PKcs are essential for the DNA damage response suggesting that the complex is involved in several chaperone pathways (Cloutier et al., 2009). Recently, RUVBL1/2 havecomplexes during the assembly of the PIKKs