Insulin-regulated aminopeptidase (IRAP) is a type II transmembrane protein with its C-terminal catalytic domain located at the cell exterior. 1,2,3,4,5 IRAP is found in almost all human tissues and is known to be expressed in neuronal cells, placental cells, and leukocytes. Similar to structurally analogous human aminopeptidase N (APN), 7,8 aminopeptidase A (APA), and mammalian endoplasmic reticulum aminopeptidases 1 (ERAP1) and ERAP2, this enzyme belongs to a family of zinc-dependent M1 metallopeptidases with a diverse set of biological roles spanning a range of cellar functions, including human hormone and glucose regulation, and cognitive function. As an insulinresponsive transporter, one of the key roles of IRAP is facilitating the translocation of glucose transporter 4 (GLUT4) to the plasma membrane in adipose tissue and skeletal muscle cells which allows the uptake of glucose from the bloodstream into these tissues, thereby regulating blood glucose levels. IRAP is therefore a target of significant pharmaceutical interest (Figure shows the crystal structure of IRAP).