In addition to AGER/RAGE, several other proteins have been identified as AGE-binding proteins. AGE binding proteins p60 and p90 (Yang et al. 1991) were subsequently identified as the Oligosaccharyl transferase 48 kDa subunit (Ost-48) and Glucosidease-2 subunit beta (Li et al. 1996). A third member was identified as Galectin-3 (Vlassara et al. 1995). These 3 proteins have been shown to be present on the plasma membrane of many cell types including vascular endothelium (Stitt et al. 1999). They have been designated AGE-R1, -R2 and -R3. Their suggested function is the removal and degradation of AGEs, but AGER-1 was found to negatively regulate AGER/RAGE (Lu et al. 2004), with kinetics that suggested a more complex interaction than simple competition for the same ligand.