pIgR

Polymeric immunoglobulin receptor (PIGR) is also known as Poly-Ig receptor, which can be cleaved into membrane secretory component (SC). PIGR is a type I transmembrane glycoprotein or a member of the immunoglobulin superfamily, and is synthesized by secretory epithelial cells and delivered to the basolateral plasma membrane where it can bind larger polymers of IgA (pIgA ) and pentameric IgM. The complex is then transported across the cell to be secreted at the apical surface. During this process a cleavage occurs that separates the extracellular (known as the secretory component) from the transmembrane segment.