PPARδ also known as PPARdelta, PPARD is a member of the peroxisome proliferator-activated receptor (PPAR) family. PPARδ protein is thought to function as an integrator of transcriptional repression and nuclear receptor signaling. It may inhibit the ligand-induced transcriptional activity of peroxisome proliferator activated receptors alpha and gamma, though evidence for this effect is inconsistent. Expression of PPARδ in colorectal cancer cells may be variable but is typically relatively low. Knockout studies in mice suggested a role for PPARδ protein in myelination of the corpus callosum, lipid metabolism, differentiation, and epidermal cell proliferation.