| Here , we identify a protein phosphatase , PH domain leucine rich repeat protein phosphatase ( PHLPP ) , that specifically dephosphorylates the hydrophobic motif of Akt ( Ser 473 in Akt 1 ) , triggering apoptosis and suppressing tumor growth . ^^^ PHLPP : a phosphatase that directly dephosphorylates Akt , promotes apoptosis , and suppresses tumor growth . ^^^ The effects of PHLPP on apoptosis are prevented in cells expressing an S473D construct of Akt , revealing that the hydrophobic motif is the primary cellular target of PHLPP . ^^^ PHLPP levels are markedly reduced in several colon cancer and glioblastoma cell lines that have elevated Akt phosphorylation . ^^^ These data are consistent with PHLPP terminating Akt signaling by directly dephosphorylating and inactivating Akt . . ^^^ |