CEP57 (centrosomal protein 57kDa), also known as PIG8, TSP57 or Translokin, is a 500 amino acid protein that localizes to both the nucleus and the cytoplasm, specifically associating with microtubules at the centrosome. Expressed ubiquitously, CEP57 exists as a homodimer that functions to mediate the mitogenic activity and nuclear translocation of FGF-2, an internalized growth factor, thereby regulating FGF-2 signaling pathways. Additionally, CEP57 is thought to play a role in spermatogenesis, possibly via the indirect regulation of gene expression. Human CEP57 shares 88% sequence identity with its mouse and bovine orthologs, suggesting a highly conserved role between species. Multiple isoforms of CEP57 exist due to alternative splicing events.