Fusion of Lysosomes with Late Endosomes Produces a Hybrid Organelle of Intermediate Density and Is NSF Dependent
| Autor: | Sally R. Gray, Barbara M. Mullock, Clare W. Fearon, J.P. Luzio, Nicholas A. Bright |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Swine
Endosome Morpholines Vesicular Transport Proteins Endosomes Biology Endocytosis Membrane Fusion Article Adenosine Triphosphate Cytosol GTP-Binding Proteins Organelle Centrifugation Density Gradient Animals Enzyme Inhibitors N-Ethylmaleimide-Sensitive Proteins Guanine Nucleotide Dissociation Inhibitors Phosphoinositide-3 Kinase Inhibitors Differential centrifugation Cell-Free System Proteolytic enzymes Membrane Proteins Lipid bilayer fusion Cell Biology Recombinant Proteins Rats Cell biology Androstadienes Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins Vesicular transport protein Liver Chromones Ethylmaleimide Guanosine Triphosphate Rab Carrier Proteins Lysosomes Wortmannin |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.140.3.591 |
| Popis: | Using a cell-free content mixing assay containing rat liver endosomes and lysosomes in the presence of pig brain cytosol, we demonstrated that after incubation at 37°C, late endosome–lysosome hybrid organelles were formed, which could be isolated by density gradient centrifugation. ImmunoEM showed that the hybrids contained both an endocytosed marker and a lysosomal enzyme. Formation of the hybrid organelles appeared not to require vesicular transport between late endosomes and lysosomes but occurred as a result of direct fusion. Hybrid organelles with similar properties were isolated directly from rat liver homogenates and thus were not an artifact of cell-free incubations. Direct fusion between late endosomes and lysosomes was an N-ethylmaleimide–sensitive factor– dependent event and was inhibited by GDP-dissociation inhibitor, indicating a requirement for a rab protein. We suggest that in cells, delivery of endocytosed ligands to an organelle where proteolytic digestion occurs is mediated by direct fusion of late endosomes with lysosomes. The consequences of this fusion to the maintenance and function of lysosomes are discussed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|