HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Published online before print January 8, 2007

This Article Full Text (Reprint (PDF)) All Versions of this Article: jlb.0806520v1 81/4/1149    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lemansky, P. Articles by Hasilik, A. Search for Related Content PubMed PubMed Citation Articles by Lemansky, P. Articles by Hasilik, A.

© by The Society for Leukocyte Biology
Journal of Leukocyte Biology, doi:10.1189/jlb.0806520

Received for publication August 17, 2006.
Revised November 2, 2006.
Accepted for publication November 28, 2006.

Article

The cation-independent mannose 6-phosphate receptor is involved in lysosomal delivery of serglycin

Institut für Physiologische Chemie, Philipps-Universität Marburg, Germany

^@ To whom correspondence should be addressed. E-mail: lemansky{at}staff.uni-marburg.de.

	Abstract

To clarify the sorting mechanism of the lysosomal/granular proteoglycan serglycin, we treated human promonocytic U937 cells with p-nitrophenyl--D-xyloside (PNP-xyl) and cycloheximide. In the absence of protein synthesis, the carbohydrate moiety of serglycin was synthesized as PNP-xyl-chondroitin sulfate (CS), and most of it was delivered to lysosomes and degraded. Further, an augmented lysosomal targeting of serglycin in the presence of tunicamycin suggested that a sorting/lectin receptor with multiple specificity was involved with an increased capacity for serglycin in the absence of N-glycosylation. Correspondingly, the cation-independent mannose 6-phosphate receptor (CI-MPR) and sortilin were observed to bind to immobilized CS. These receptors were eluted in the presence of 200-400 mM and 100-250 mM NaCl, respectively. After treating the cells with a cross-linking reagent, a portion of the sulfated proteoglycan was coimmunoprecipitated with the CI-MPR but not with sortilin. In the presence of phorbol ester, lysosomal targeting of serglycin and to a lesser extent, of cathepsin D was inhibited. We conclude that the CI-MPR participates in lysosomal and granular targeting of serglycin and basic proteins such as lysozyme associated with the proteoglycan in hematopoietic cells.

Key Words: chondroitin sulfate • lysozyme • phorbol ester • sortilin

This article has been cited by other articles:

				N. M Dahms, L. J Olson, and J.-J. P Kim Strategies for carbohydrate recognition by the mannose 6-phosphate receptors Glycobiology, September 1, 2008; 18(9): 664 - 678. [Abstract] [Full Text] [PDF]