Journal article
Relationship between endosomes and lysosomes
Biochemical Society transactions, Vol.29(4), pp.476-480
08/01/2001
DOI: 10.1042/bst0290476
PMID: 11498012
Abstract
Delivery of endocytosed macromolecules to lysosomes occurs by means of direct fusion of late endosomes with lysosomes. This has been formally demonstrated in a cell-free content mixing assay using late endosomes and lysosomes from rat liver. There is evidence from electron microscopy studies that the same process occurs in intact cells. The fusion process results in the formation of hybrid organelles from which lysosomes are reformed. The discovery of the hybrid organelle has opened up three areas of investigation: (i) the mechanism of direct fusion of late endosomes and lysosomes, (ii) the mechanism of re-formation of lysosomes from the hybrid organelle, and (iii) the function of the hybrid organelle. Fusion has analogies with homotypic vacuole fusion in yeast. It requires syntaxin 7 as part of the functional trans-SNARE [SNAP receptor, where SNAP is soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein] complex and the release of lumenal calcium to achieve membrane fusion. Reformation of lysosomes from the hybrid organelle occurs by a maturation process involving condensation of lumenal content and probably removal of some membrane proteins by vesicular traffic. Lysosomes may thus be regarded as a type of secretory granule, storing acid hydrolases in between fusion events with late endosomes. The hybrid organelle is predicted to function as a ‘cell stomach’, acting as a major site of hydrolysis of endocytosed macromolecules.
Details
- Title: Subtitle
- Relationship between endosomes and lysosomes
- Creators
- J. P. Luzio - University of CambridgeB. M. Mullock - University of CambridgeP. R. Pryor - University of CambridgeM. R. Lindsay - University of CambridgeD. E. James - University of QueenslandR. C. Piper - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Biochemical Society transactions, Vol.29(4), pp.476-480
- DOI
- 10.1042/bst0290476
- PMID
- 11498012
- ISSN
- 0300-5127
- eISSN
- 1470-8752
- Language
- English
- Date published
- 08/01/2001
- Academic Unit
- Molecular Physiology and Biophysics; Medicine Administration; Internal Medicine
- Record Identifier
- 9984297613302771
Metrics
10 Record Views