The folate receptor beta (FOLR2, FBP) binds folate (FOLA) and reduced folic acid derivatives and mediates their delivery into cells (Antony et al. 1985). After ligand binding, the resultant complex is endocytosed into the cell where ligand release occurs in the acidic environment of the recycling endosome (Wibowo et al. 2013). For simplicity, the overall transport of FOLA from the extracellular region to the cytosol of a cell is described here.