The cation-independent mannose 6-phosphate receptor precursor, MPR or IGF2R, of 2491 aas and 2 TMSs.  MPR transports phosphorylated lysosomal enzymes from the Golgi complex and the cell surface to lysosomes. Lysosomal enzymes bearing phosphomannosyl residues bind specifically to mannose-6-phosphate receptors in the Golgi apparatus and the resulting receptor-ligand complex is transported to an acidic prelysosomal compartment where the low pH causes dissociation of the complex. This receptor also binds IGF2. It acts as a positive regulator of T-cell coactivation by binding DPP4 (Ikushima et al. 2000).