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Assessment of the Roles of Ordered Lipid Microdomains in Post‐Endocytic Trafficking of Glycosyl‐Phosphatidylinositol‐Anchored Proteins in Mammalian Fibroblasts
Author(s) -
Refaei Mohammad,
Leventis Rania,
Silvius John R.
Publication year - 2011
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.1600-0854.2011.01206.x
Subject(s) - endosome , endocytic cycle , microbiology and biotechnology , endocytosis , folate receptor , lipid raft , biology , lipid microdomain , baby hamster kidney cell , transferrin receptor , vesicular transport proteins , receptor , biochemistry , membrane , vacuolar protein sorting , cell , cancer cell , genetics , cancer
We have used artificial phosphatidylethanolamine‐polyethylene glycol (PE‐PEG)‐anchored proteins, incorporated into living mammalian cells, to evaluate previously proposed roles for ordered lipid ‘raft’ domains in the post‐endocytic trafficking of glycosylphosphatidylinositol (GPI)‐anchored proteins in CHO and BHK cells. In CHO cells, endocytosed PE‐PEG protein conjugates colocalized strongly with the internalized GPI‐anchored folate receptor, concentrating in the endosomal recycling compartment, regardless of the structure of the hydrocarbon chains of the PE‐PEG ‘anchor’. However, internalized PE‐PEG protein conjugates with long‐chain saturated anchors recycled to the plasma membrane at a slow rate comparable to that measured for the GPI‐anchored folate receptor, whereas conjugates with short‐chain or unsaturated anchors recycled at a faster rate similar to that observed for the transferrin receptor. These findings support the proposal (Mayor et al. Cholesterol‐dependent retention of GPI‐anchored proteins in endosomes. EMBO J 1998;17:4628–4638) that the slow recycling of GPI proteins in CHO cells rests on their affinity for ordered lipid domains. In BHK cells, internalized PE‐PEG protein conjugates with either saturated or unsaturated ‘anchors’ colocalized strongly with simultaneously endocytosed folate receptor and, like the folate receptor, gradually accumulated in late endosomes/lysosomes. These latter findings do not support previous suggestions that the sorting of GPI proteins to late endosomes in BHK cells depends on their association with lipid rafts.