Enhances the phosphorylation and activation of AKT1, AKT2 and AKT3. Promotes nuclear translocation of AKT1. Enhances cell proliferation, stabilizes mitochondrial membrane potential and promotes cell survival. Homodimer. Interacts with AKT1, AKT2 and AKT3 (via PH domain). Interacts with PNPT1; the interaction has no effect on PNPT1 exonuclease activity. Microsomal fraction. Restricted in the T-cell lineage to immature thymocytes and activated peripheral lymphocytes. Preferentially expressed early in T- and B-lymphocyte differentiation. Chromosomal aberrations activating TCL1A are found in chronic T-cell leukemias (T-CLL). Translocation t(14;14)(q11;q32); translocation t(7;14)(q35;q32); inversion inv(14)(q11;q32) that involves the T-cell receptor alpha/delta loci. Belongs to the TCL1 family.