G2 And S-Phase Expressed Protein 1 (GTSE1)

GTSE1 is only expressed in the S and G2 phases of the cell cycle, where it colocalizes with cytoplasmic tubulin and microtubules. In response to DNA damage, the encoded protein accumulates in the nucleus and binds the tumor suppressor protein p53, shuttling it out of the nucleus and repressing its ability to induce apoptosis.

The deduced 720-amino acid protein shares 65% sequence identity with mouse Gtse1. Western blot analysis of transiently transfected COS-7 cells revealed an apparent molecular mass of about 110 kD. Transient transfection of osteosarcoma cells resulted in immunofluorescent localization of GTSE1 to microtubules and colocalization with tubulin.