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Extracting Modified Microtubules from Mammalian Cells to Study Microtubule-Protein Complexes by Cryo-Electron Microscopy
Published on: March 3, 2023
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Structural differences between yeast and mammalian microtubules revealed by cryo-EM
Stuart C Howes1, Elisabeth A Geyer2,3, Benjamin LaFrance4
1Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA.
The Journal of Cell Biology
|June 28, 2017
Summary
Structural differences in microtubules between yeast and mammals impact polymerization dynamics. The protein Bim1 binds differently, causing yeast microtubule compaction and disassembly.
Area of Science:
- Cell biology
- Biochemistry
- Structural biology
Background:
- Microtubules, polymers of αβ-tubulin heterodimers, are vital for eukaryotic cells.
- Significant structural variations exist between in vitro assembled mammalian and yeast microtubules despite sequence conservation.
Purpose of the Study:
- To investigate the structural and dynamic differences between yeast and mammalian microtubules.
- To elucidate the binding mechanism and effects of the microtubule plus end-tracking protein Bim1 on yeast microtubules.
Main Methods:
- In vitro assembly of microtubules from mammalian and yeast tubulin.
- Cryo-electron microscopy to visualize microtubule structures.
- Analysis of Bim1 binding interactions and effects on microtubule dynamics.
Main Results:
- Yeast microtubules do not compact at the interdimer interface upon GTP hydrolysis, unlike mammalian microtubules.
- Bim1 binds yeast microtubules both between and within tubulin dimers, but mammalian tubulin only at interdimer contacts.
- Bim1 induces compaction and rapid disassembly of yeast microtubules at cryo-EM concentrations.
Conclusions:
- Structural disparities between yeast and mammalian microtubules contribute to differing polymerization dynamics.
- These differences may represent adaptations to yeast or mammalian cellular environments and growth conditions.
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