This family is the N-terminus of GTSE1 proteins. GTSE-1 (G2 and S phase-expressed-1) protein is specifically expressed during S and G2 phases of the cell cycle. It is mainly localized to the microtubules and when overexpressed delays the G2 to M transition. the full protein negatively regulates p53 transactivation function, protein levels, and p53-dependent apoptosis. This domain family is found in eukaryotes, and is approximately 140 amino acids in length. There is a conserved FDFD sequence motif.