Glycobiology Advance Access originally published online on July 11, 2008
Glycobiology 2008 18(9):664-678; doi:10.1093/glycob/cwn061
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Review |
Strategies for carbohydrate recognition by the mannose 6-phosphate receptors
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
1 To whom correspondence should be addressed: Tel: +1-414-456-4698; Fax: +1-414-456-6510; e-mail: ndahms{at}mcw.edu and jjkim{at}mcw.edu
Received on April 17, 2008; revised on June 19, 2008; accepted on June 19, 2008
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 
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.
Key words: lectin / lysosome / mannose 6-phosphate receptor / protein targeting