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Minus-end-directed motion of kinesin-coated microspheres driven by microtubule depolymerization
V A Lombillo1, R J Stewart, J R McIntosh
1Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309.
Nature
|January 12, 1995
Summary
Motor proteins like kinesin can move cellular components along microtubules during depolymerization. This study uses a refined assay to investigate proteins coupling microtubule dynamics with motility.
Area of Science:
- Cell Biology
- Biophysics
- Molecular Motors
Background:
- Microtubule (MT) dynamics, including polymerization and depolymerization, are crucial for intracellular motility.
- Identifying proteins that link MT dynamics to cargo movement is challenging due to the complexity of cellular components like chromosomes.
Purpose of the Study:
- To investigate proteins that facilitate disassembly-dependent motion along microtubules.
- To refine an in vitro motility assay for studying the coupling of MT dynamics and motor activity.
Main Methods:
- Developed a motility assay using protein-coated latex microspheres instead of chromosomes.
- Utilized MTs grown from and tethered to Tetrahymena pellicles.
- Investigated the role of motor proteins, specifically kinesin, in microsphere movement on disassembling MTs.
Main Results:
- Demonstrated that enzymes, including kinesin, can drive the in vitro motility of microspheres on disassembling MTs.
- Showed that MT disassembly can reverse the polarity of kinesin's motor activity.
- Observed that motor-MT interactions can modulate the rate of tubulin depolymerization.
Conclusions:
- Kinesin and potentially other motor proteins can mediate cargo transport dependent on microtubule depolymerization.
- MT disassembly is a significant factor influencing motor protein activity and directionality.
- The refined assay provides a simplified system to study the interplay between MT dynamics and motor-driven transport.