PDZ domain-containing protein 11, also known as AIPP1a, PISP, PDZD11 and PDZK11, is a cytosolic protein that contains one PDZ (DHR) domain. PDZD11 bears resemblance to members of the MALS / VELIS family of proteins. It contains but one PDZ domain that apparently interacts with the C-terminus of partner proteins. PDZD11 is ubiquitously expressed, and appears to target calcium and copper ATPases to basolateral cell membranes. PDZD11 is a transiently interacting partner of the PMCA b-splice forms that may play a role in their sorting to or from the plasma membrane. Full-length human PDZD11 shares 97% amino acids (aa) identity with mouse PDZD11.