| Here we show that , in contrast to Akt 1 and Akt 2 , which bind to all members of the TCL 1 family , Akt 3 specifically interacts with TCL 1 but not with MTCP 1 or TCL1b . ^^^ This association is functional , as the presence of TCL 1 but not MTCP 1 or TCL1b increased Akt 3 kinase activity in in vitro kinase assays . ^^^ Functional specificity is determined by the Akt pleckstrin homology domain as chimeric Akt 1 , where Akt 1 PH domain was replaced by that of Akt 3 was no longer able to interact with MTCP 1 or TCL1b and its kinase activity was solely enhanced by TCL 1 . ^^^ Moreover , we show that , in TCL 1 overexpressing SUPT 11 T cell leukemia and P3HR 1 Burkitt ' s lymphoma cell lines , TCL 1 interacts with endogenous Akt 1 , Akt 2 , and Akt 3 . ^^^ TCL 1 enhanced hetero oligomerization of Akt 1 with Akt 3 and as a consequence facilitated transphosphorylation of Akt molecules , which may contribute to Akt activation and TCL 1 induced leukemogenesis in vivo . . ^^^ |