Apical Cargo Traverses Endosomal Compartments on the Passage to the Cell Surface
| Autor: | Catharina I. Cramm-Behrens, Ralf Jacob, Martina Dienst |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Endosome
Gene Expression Golgi Apparatus Endosomes Biology Biochemistry Cell Line symbols.namesake Dogs Genes Reporter Structural Biology Chlorocebus aethiops Genetics Animals Lactase-Phlorizin Hydrolase RNA Small Interfering Molecular Biology Lipid raft Epithelial polarity Vesicle Cell Membrane Cell Biology Golgi apparatus Apical membrane Fusion protein Sucrase-Isomaltase Complex Cell biology Kinetics Protein Transport rab GTP-Binding Proteins symbols lipids (amino acids peptides and proteins) Rab |
| Zdroj: | Traffic. 9:2206-2220 |
| ISSN: | 1600-0854 1398-9219 |
| Popis: | Epithelial polarity is based on intracellular sorting machinery that maintains the asymmetric distribution of lipids and proteins to the cell surface. Dependent on their lipid raft affinity, newly synthesized apical polypeptides are segregated into distinct vesicle populations subsequent to the passage through the Golgi apparatus. Using a combined fluorescence microscopic and biochemical approach, we found that lipid raft-associated sucrase-isomaltase (SI) as well as non-raft-associated lactase-phlorizin hydrolase (LPH) traverse endosomal compartments before entering the apical membrane. Fluorescent fusion proteins of both hydrolases were co-stained with Rab4-, Rab8- and Rab11-positive endosomes in polarized Madin-Darby canine kidney and non-polarized COS-1 cells. Immunoisolation of post-Golgi vesicles subsequent to different times of TGN release revealed that LPH and SI navigate in chronological order through Rab4-, Rab8- and Rab11-positive endosomes. Thereafter, the two hydrolases are segregated into distinct vesicle populations. In addition, apical membrane traffic could be significantly inhibited by RNA interference-mediated depletion of these guanosine triphosphatases. These results suggest that in epithelial cells, lipid raft-dependent and -independent apical cargo follow a transendosomal route. |
| Databáze: | OpenAIRE |
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