SAM Pointed Domain Containing Ets Transcription Factor (SPDEF)

PDEF is an ETS transcription factor expressed in prostate epithelial cells. It acts as an androgen-independent transactivator of PSA expression. The deduced 335-amino acid protein has a calculated molecular mass of 37.5 kD. PDEF contains 2 putative PEST sequences, one near the N terminus and the other at the center of the protein, a central pointed domain, which is characteristic of some ETS family members and weakly homologous to the SAM protein-protein interaction domain of polycomb proteins and Eph receptors, and an ETS DNA-binding domain. It also has several potential phosphorylation sites, including 8 mitogen-activated protein kinase (MAPK) phosphorylation sites, 5 of which are clustered at the N terminus. Northern blot analysis detected a 2.0-kb transcript expressed almost exclusively in prostate gland.