IMPAD1 protein (IMPA3, gPAPP or IMPase 3) belongs to the inositol monophosphatase family. It is found in Purkinje cells, brain stem, lung and chondrocytes. Mouse IMPAD1 gene encodes a type II transmembrane Golgi-embedded glycoprotein with 356 amino acid residues which generates a 306 amino acid residues mature protein after processing. It is expressed in embryo, and in theory may catalyze myo-inositol monophosphate to myo-inositol. Free myo-inositol is used to generate inositol phospholipid, an essential component of intracellular signaling pathways that mobilize calcium. Mouse IMPAD1 exhibits 91% sequence identity with the human homologue.