Strategies for carbohydrate recognition by the mannose 6-phosphate receptors.
The two members of the P-type lectin family, the 46 kDa cation-dependent mannose 6-phosphate receptor (CD-MPR) and the 300 kDa cation-independent mannose 6-phosphate receptor (CI-MPR), are ubiquitously expressed throughout the animal kingdom and are distinguished from all other lectins by their ability to recognize phosphorylated mannose residues. The best-characterized function of the MPRs is their ability to direct the delivery of approximately 60 different newly synthesized soluble lysosomal enzymes bearing mannose 6-phosphate (Man-6-P) on their N-linked oligosaccharides to the lysosome. In addition to its intracellular role in lysosome biogenesis, the CI-MPR, but not the CD-MPR, participates in a number of other biological processes by interacting with various molecules at the cell surface. The list of extracellular ligands recognized by this multifunctional receptor has grown to include a diverse spectrum of Man-6-P-containing proteins as well as several non-Man-6-P-containing ligands. Recent structural studies have given us a clearer view of how these two receptors use related, but yet distinct, approaches in the recognition of phosphomannosyl residues.
Dahms
Nancy M
NM
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA. ndahms@mcw.edu
Olson
Linda J
LJ
Kim
Jung-Ja P
JJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D050260:Carbohydrate Metabolism / Q000502:physiology; D018360:Crystallography, X-Ray; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008360:Mannosephosphates / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000378:metabolism; D011485:Protein Binding; D017527:Receptor, IGF Type 2 / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D006023:Glycoproteins; D008360:Mannosephosphates; D009844:Oligosaccharides; D017527:Receptor, IGF Type 2; C027693:mannose-6-phosphate