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In Vitro Polymerization of F-actin on Early Endosomes
Published on: August 28, 2017
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Early endosome motility spatially organizes polysome distribution
Yujiro Higuchi1, Peter Ashwin, Yvonne Roger
1Biosciences and 2 Mathematics Research Institute, University of Exeter, Exeter EX4 4QD, England, UK.
The Journal of Cell Biology
|February 5, 2014
Summary
Early endosomes (EEs) distribute the translation machinery by hitchhiking on motor proteins. This process is crucial for cell growth, as impaired EE motility restricts ribosome transport and protein synthesis.
Area of Science:
- Cell Biology
- Molecular Biology
- Biophysics
Background:
- Early endosomes (EEs) are known for protein sorting and neuronal signaling.
- Cytoskeleton-dependent motility of EEs is essential for cellular functions.
Purpose of the Study:
- To investigate the role of EE motility in distributing the translation machinery.
- To understand the mechanism of ribosome and mRNA transport within the cell.
Main Methods:
- Visualization of ribosomal subunit proteins and polysomes.
- Analysis of polysome movement along microtubules via EEs.
- Modeling of motor-driven transport dynamics.
- Genetic manipulation of motor proteins and RNA-binding proteins (Rrm4).
Main Results:
- Large ribosomal subunits diffused slowly, while polysomes exhibited long-range motility.
- Polysomes hitched rides on kinesin-3 and dynein-driven EEs, translating associated mRNA.
- Impaired EE motility or Rrm4 binding reduced ribosome transport and caused nuclear aggregation.
- Cell growth was severely restricted in mutants with impaired EE motility.
Conclusions:
- EE motility plays an unexpected role in distributing the protein translation machinery.
- Polysome association with moving EEs and subsequent "off- and reloading" is a key mechanism for ribosome distribution.
- This process is vital for maintaining cellular growth and function.
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