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Direct Force Measurements of Subcellular Mechanics in Confinement using Optical Tweezers
Published on: August 31, 2021
Quantitative optical trapping on single organelles in cell extract
Pradeep Barak1, Ashim Rai, Priyanka Rai
1Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
Nature Methods
|December 18, 2012
Summary
We developed VMatch, an optical trapping method to measure motor protein force on single organelles. This technique was used to analyze kinesin-1 activity on lipid droplets from rats under different feeding conditions.
Area of Science:
- Cell Biology
- Biophysics
- Molecular Motors
Background:
- Motor proteins like kinesin-1 are crucial for intracellular transport.
- Understanding motor protein function requires precise force measurements on native complexes.
- Organelle size variability complicates force measurements.
Purpose of the Study:
- To develop a novel optical trapping method (VMatch) for measuring motor protein force on single organelles of unknown size.
- To functionally interrogate native motor complexes in cell extracts.
- To quantify kinesin-1 force, number, and activity on lipid droplets from rats under varying nutritional states.
Main Methods:
- Development of VMatch, a precise optical trapping technique.
- Isolation of motile lipid droplets from rat liver cells.
- Application of VMatch to measure kinesin-1 force, number, and activity on isolated lipid droplets.
Main Results:
- VMatch enables precise force measurements on single organelles without prior size knowledge.
- Kinesin-1 force, number, and activity were quantified on lipid droplets.
- Differences in kinesin-1 function were observed between fed and food-deprived rats (specific results not detailed in abstract).
Conclusions:
- VMatch is a powerful tool for studying native motor protein function.
- The study provides insights into the regulation of kinesin-1 activity on lipid droplets in response to nutritional status.
