Endosome-lysosome Fusion
Endosome-lysosome Fusion - Related Videos
08:15
Quantification of Endosome and Lysosome Motilities in Cultured Neurons Using Fluorescent Probes
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Cited by 6 •
2017
The investigation of membrane trafficking is crucial for understanding neuronal functions. Here, we introduce a method for quantifying vesicle motility in neurons. This is a convenient method that can be adapted to the quantification of membrane trafficking in the nervous system.
10:51
Visualization of Endosome Dynamics in Living Nerve Terminals with Four-dimensional Fluorescence Imaging
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2014
Four-dimensional (4D) imaging is utilized to study the behavior and interactions among two types of endosomes in living vertebrate nerve terminals. Movement of these small structures is characterized in three dimensions, permitting confirmation of events such as endosome fusion and exocytosis.
12:15
In Vitro Polymerization of F-actin on Early Endosomes
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Cited by 3 •
2017
Early endosome functions depend on F-actin polymerization. Here, we describe a microscopy-based in vitro assay that reconstitutes the nucleation and polymerization of F-actin on early endosomal membranes in test tubes, thus rendering this complex series of reactions amenable to biochemical and genetic manipulations.
09:49
Nanogold Labeling of the Yeast Endosomal System for Ultrastructural Analyses
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Cited by 1 •
2014
Yeast, Saccharomyces cerevisiae, has been a key model organism to identify and study genes regulating the biogenesis and functions of the endosomal system. Here we present a detailed protocol for the specific labeling of the endosomal compartments for ultrastructural studies.
02:58
Nanoparticle-Mediated Visualization of Endo-Lysosomal Remodeling in Bacterially-Infected Cells
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2025
Source: Zhang, Y., et al. Application of Fluorescent Nanoparticles to Study Remodeling of the Endo-lysosomal System by Intracellular Bacteria. J. Vis. Exp. (2015)This video demonstrates the use of fluorescent nanoparticles to visualize endo-lysosomal remodeling in human epithelial cells infected by intracellular bacteria. Following bacterial invasion, the pathogens manipulate the host cytoskeleton and endo-lysosomal system, forming vacuoles with tubular projections that alter vesicle transport.
FAQs
Rab7 marks late endosomes as fusion-competent compartments, while the HOPS complex helps organize the machinery needed for docking and membrane merger. Their activity links endosomal maturation to the next delivery stage rather than treating fusion as a spontaneous event. In pharmacology, disturbances in this coordination can change how efficiently internalized receptors, drugs, or therapeutic cargo reach lysosomes.
SNARE-mediated fusion supplies the final membrane-merging step after Rab7 and HOPS have established fusion competence. This division of labor separates recognition and preparation from the physical joining of membranes. Keeping these stages distinct helps explain why a cell may have mature late endosomes yet still show impaired cargo delivery if the fusion machinery does not complete membrane merger.
Lysosomal acidification acts after delivery and creates conditions that support enzymatic cargo breakdown. Successful membrane fusion therefore does not by itself guarantee complete processing, because cargo must also encounter an acidic lysosomal environment. This distinction matters pharmacologically because altered trafficking and altered degradation can produce different effects on receptor persistence, intracellular drug handling, and the fate of biologic or nanoparticle cargo.
Endosome-lysosome fusion can influence receptor downregulation by determining whether internalized receptors reach lysosomes, where associated cargo can undergo degradation. Because receptor handling affects signaling, changes in this trafficking route may alter cellular responses to pharmacological agents. The pathway therefore provides important context for interpreting drug effects that depend on receptor removal after endocytosis.
Nanoparticle and biologic therapies require consideration of intracellular trafficking because their cargo may be routed through endosomal and lysosomal compartments. Endosome-lysosome fusion can influence how these therapies are handled within the cell and whether they encounter lysosomal degradation. Studying the pathway can therefore help relate subcellular trafficking patterns to therapeutic efficacy and possible toxicity.
Cargo delivery to lysosomes and the acidic environment that supports enzymatic breakdown provide relevant context for antigen processing. Endosome-lysosome fusion is therefore important when pharmacological studies examine how internalized material is routed before processing. This connection broadens the pathway's significance beyond degradation alone, linking intracellular membrane trafficking with immune-related handling of cargo.
Altered fusion can change drug efficacy and toxicity because it affects the intracellular destination and processing of endocytosed material. Consequences may differ according to whether a therapy depends on receptor downregulation, lysosomal breakdown, antigen processing, or trafficking involving nanoparticles or biologics. Fusion status is therefore a relevant variable when interpreting cellular drug responses and therapeutic outcomes.