Premium
Glycosaminoglycan Chains Affect Exocytic and Endocytic Protein Traffic
Author(s) -
Kobialka Szymon,
Beuret Nicole,
BenTekaya Houchaima,
Spiess Martin
Publication year - 2009
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.1600-0854.2009.00987.x
Subject(s) - endocytosis , endosome , microbiology and biotechnology , endocytic cycle , proteoglycan , biology , golgi apparatus , chondroitin sulfate , glycosaminoglycan , brefeldin a , internalization , transport protein , asialoglycoprotein receptor , biochemistry , extracellular matrix , receptor , intracellular , endoplasmic reticulum , hepatocyte , in vitro
Protein glycosylation such as N‐ and O‐linked glycans as well as glycosaminoglycans (GAGs) have been shown to contribute to polarized sorting in epithelial cells. Here, we analyzed the effect of GAGs more generally on protein traffic also in non‐polarized cells. Using short sequence tags of 10–17 amino acids encoding known GAG attachment sites, we have converted the asialoglycoprotein receptor H1, which constitutively cycles between the plasma membrane and endosomes, into a proteoglycan. Expressed in HeLa cells, the receptor was almost completely modified with a chondroitin sulfate chain and could be efficiently labeled by [ 35 S]sulfation. GAG attachment altered the steady‐state distribution of the receptor by inhibiting endocytosis, while recycling was not affected. The reduced internalization is not the result of immobilization by interaction with the extracellular matrix, because fluorescence recovery after photobleaching did not detect an increased immobile fraction nor even a significant change in mobility. GAG chains furthermore accelerated Golgi‐to‐cell surface transport of H1. The same acceleration of export was also observed for a GAG‐tagged version of the secretory protein α1‐protease inhibitor, suggesting that this effect acts generally on proteoglycans, possibly by directing them into distinct carriers. Our results show novel roles of GAGs in protein sorting also in non‐polarized cells.