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N‐Glycans Mediate Apical Recycling of the Sialomucin Endolyn in Polarized MDCK Cells
Author(s) -
Potter Beth A.,
Weixel Kelly M.,
Bruns Jennifer R.,
Ihrke Gudrun,
Weisz Ora A.
Publication year - 2006
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2005.00371.x
Subject(s) - biology , microbiology and biotechnology , glycan , glycoprotein
Apical and basolateral proteins are maintained within distinct membrane subdomains in polarized epithelial cells by biosynthetic and postendocytic sorting processes. Sorting of basolateral proteins in these processes has been well studied; however, the sorting signals and mechanisms that direct proteins to the apical surface are less well understood. We previously demonstrated that an N‐glycan‐dependent sorting signal directs the sialomucin endolyn to the apical surface in polarized Madin‐Darby canine kidney cells. Terminal processing of a subset of endolyn's N‐glycans is key for polarized biosynthetic delivery to the apical membrane. Endolyn is subsequently internalized, and via a cytoplasmic tyrosine‐based sorting motif is targeted to lysosomes from where it constitutively cycles to the cell surface. Here, we examine the polarized sorting of endolyn along the postendocytic pathway in polarized cells. Our results suggest that similar N‐glycan sorting determinants are required for apical delivery of endolyn along both the biosynthetic and the postendocytic pathways.