B-Cell Translocation Gene 2 (BTG2)

The protein BTG2 is the human homolog of the PC3 protein in rat and of the Tis21 protein in mouse.Tis21 had been originally isolated as a sequence induced by TPA in mouse fibroblasts, whereas PC3 was originally isolated as sequence induced at the beginning of neuron differentiation; BTG2 was then isolated in human cells as sequence induced by p53 and DNA damage.

BTG2 is a member of the BTG/Tob family . This family has structurally related proteins that appear to have antiproliferative properties. In particular, the BTG2 protein has been shown to negatively control a cell cycle checkpoint at the G₁ to S phase transition in fibroblasts and neuronal cells by direct inhibition of the activity of cyclin D1 promoter.