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In Vitro Polymerization of F-actin on Early Endosomes
Published on: August 28, 2017
Plasticity of early endosomes
R G Parton1, P Schrotz, C Bucci
1European Molecular Biology Laboratory, Heidelberg, Germany.
Journal of Cell Science
|October 1, 1992
Summary
Early endosomes show remarkable plasticity. Avidin-biotin cross-linking of cell surface proteins dramatically enlarges these organelles, altering their structure and function without halting membrane traffic.
Area of Science:
- Cell Biology
- Membrane Trafficking
- Endocytosis
Background:
- Early endosomes are crucial for intracellular sorting and transport.
- Their dynamic structural organization is essential for cellular function.
Purpose of the Study:
- To investigate the plasticity of early endosomes in vivo.
- To understand how cross-linking of cell surface proteins affects early endosome structure and dynamics.
Main Methods:
- Cell surface biotinylation followed by avidin treatment.
- Quantitative electron microscopy.
- Overexpression of a rab5 mutant.
Main Results:
- Avidin-biotin treatment induced significant enlargement of early endosomes, forming large, electron-dense structures.
- Fluid-phase tracer accumulation increased, indicating altered endosomal uptake.
- Endosomal compartment volume increased, but surface area relative to volume decreased.
- Rab5 mutant overexpression prevented enlargement and caused fragmentation, implicating fusion in the process.
Conclusions:
- Early endosomes possess significant in vivo plasticity.
- Avidin-biotin cross-linking interferes with this dynamic process but does not completely block membrane traffic.
- Early endosome fusion plays a key role in maintaining their structural integrity and dynamic behavior.
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