A New Mutational aktivation in the PI3K Pathway

Although multiple members of the phosphatidylinositol-3-kinase pathway (PI3K) are targeted by germline or somatic mutations, functional mutations in the three akt isoforms have proven elusive. This is somewhat surprising, as AKT represents a key node in the PI3K pathway, exhibiting transforming activity when incorporated into the AKT8 retrovirus. A recent report in Nature identifies a transforming E17K PH domain mutation in akt1 in breast (8%), colorectal (6%), and ovarian (2%) cancers. E17K-akt1 transforming activity appears due to PtdIns(3,4)P2- and PtdIns(3,4,5)P3-independent recruitment of AKT1 to the membrane. This novel observation raises important theoretical and clinical questions. Although multiple members of the phosphatidylinositol-3-kinase pathway (PI3K) are targeted by germline or somatic mutations, functional mutations in the three akt isoforms have proven elusive. This is somewhat surprising, as AKT represents a key node in the PI3K pathway, exhibiting transforming activity when incorporated into the AKT8 retrovirus. A recent report in Nature identifies a transforming E17K PH domain mutation in akt1 in breast (8%), colorectal (6%), and ovarian (2%) cancers. E17K-akt1 transforming activity appears due to PtdIns(3,4)P2- and PtdIns(3,4,5)P3-independent recruitment of AKT1 to the membrane. This novel observation raises important theoretical and clinical questions.