Relationship between endosomes and lysosomes

Luzio, J. P., Mullock, B. M., Pryor, P. R., Lindsay, M. R., James, D. E. and Piper, R. C. (2001) Relationship between endosomes and lysosomes. Biochemical Society Transactions, 29 4: 476-480. doi:10.1042/BST0290476

Author Luzio, J. P.
Mullock, B. M.
Pryor, P. R.
Lindsay, M. R.
James, D. E.
Piper, R. C.
Title Relationship between endosomes and lysosomes
Journal name Biochemical Society Transactions   Check publisher's open access policy
ISSN 0300-5127
Publication date 2001
Sub-type Article (original research)
DOI 10.1042/BST0290476
Volume 29
Issue 4
Start page 476
End page 480
Total pages 5
Place of publication United Kingdom
Publisher Portland Press
Collection year 2001
Language eng
Subject C1
320600 Medical Physiology
780105 Biological sciences
0601 Biochemistry and Cell Biology
1101 Medical Biochemistry and Metabolomics
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.
Keyword Biochemistry & Molecular Biology
Endocytic Pathway
Late-endosome-lysosome Hybrid Organelle
Tethering Proteins
Receptor Complexes
Hybrid Organelles
Vacuole Fusion
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: Institute for Molecular Bioscience - Publications
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 44 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 46 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Tue, 14 Aug 2007, 16:58:36 EST