 SubAB's target is in the endoplasmic reticulum of the cell and is brought into the cell through clathrin-mediated endocytosis.The glycan receptor for SubAB usually ends with an α2-3-linked N-Glycolylneuraminic acid (Neu5Gc).SubAB has an A subunit where it acts as a serine protease and cleaves Bip/GRP78, an endoplasmic reticulum chaperone.