May coordinately regulate cell cycle progression and transcription during spermatogenesis. Inhibits degradation of polyubiquitinated cyclin A and cyclin B1 and thereby arrests the cell cycle at early M phase. ESXR1-N acts as a transcriptional repressor. Binds to the sequence 5'-TAATGTTATTA-3' which is present within the first intron of the KRAS gene and inhibits its expression. ESXR1-C has the ability to inhibit cyclin turnover. ESXR1-N localizes specifically to the nucleus while ESXR1-C localizes specifically to the cytoplasm. Expressed in placenta and testis. Expressed in testicular germ cell tumors. Undergoes proteolytic cleavage; produces a 45 kDa N-terminal homeodomain-containing fragment (ESXR1-N) and a 20 kDa C-terminal fragment (ESXR1-C).