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Kinectin, a major kinesin-binding protein on ER
I Toyoshima1, H Yu, E R Steuer
1Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710.
The Journal of Cell Biology
|September 1, 1992
Summary
Researchers identified kinectin, a novel 160-kD integral membrane protein, as a key receptor that binds kinesin to cellular organelles for microtubule-based transport.
Area of Science:
- Cell Biology
- Molecular Motors
- Membrane Trafficking
Background:
- Microtubule-based organelle transport relies on membrane receptors.
- Kinesin is a motor protein crucial for this transport.
- No specific kinesin-binding membrane proteins had been previously identified.
Purpose of the Study:
- To isolate and characterize the membrane protein responsible for binding kinesin.
- To understand the role of this protein in organelle transport.
Main Methods:
- Antibody-based affinity purification using kinesin.
- Velocity sedimentation of solubilized microsomes.
- Alkaline extraction and kinesin affinity chromatography.
- Biochemical characterization and immunofluorescence microscopy.
Main Results:
- A 160-kD protein was co-isolated with kinesin from chick embryo brain microsomes.
- This 160-kD protein is an integral membrane protein located on the cytoplasmic face.
- The protein, named kinectin, was found to be enriched in fractions with high microtubule-dependent motility.
- Immunofluorescence showed kinectin localizes to the endoplasmic reticulum.
Conclusions:
- Kinectin is identified as a major kinesin-binding protein on motile vesicles.
- This protein likely serves as the receptor for kinesin on organelle membranes.
- Kinectin plays a critical role in kinesin-mediated organelle transport.