PERP (p53 effector related to PMP-22) is a p53/p63 target gene involved in DNA damage-induced apoptosis (Flores et al. 2002). It is a tetraspan membrane protein,distantly related to members of the claudin/PMP-22/EMP family of four-pass membrane proteins (Attardi et al. 2000). It has an epithelial-specific expression pattern during embryogenesis and localizes to desmosomes. Perp -/- knockout mice exhibit numerous desmosomal structural defects, suggesting a role for Perp in promoting the stable assembly of desmosomal adhesive complexes (Ihrie et al. 2005).