Funding Organization(s): National Science Foundation (NSF, United States); National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
Microtubules are polymers of αβ-tubulin heterodimers essential for all eukaryotes. Despite sequence conservation, there are significant structural differences between microtubules assembled in vitro from mammalian or budding yeast tubulin. Yeast MTs ...
Microtubules are polymers of αβ-tubulin heterodimers essential for all eukaryotes. Despite sequence conservation, there are significant structural differences between microtubules assembled in vitro from mammalian or budding yeast tubulin. Yeast MTs were not observed to undergo compaction at the interdimer interface as seen for mammalian microtubules upon GTP hydrolysis. Lack of compaction might reflect slower GTP hydrolysis or a different degree of allosteric coupling in the lattice. The microtubule plus end-tracking protein Bim1 binds yeast microtubules both between αβ-tubulin heterodimers, as seen for other organisms, and within tubulin dimers, but binds mammalian tubulin only at interdimer contacts. At the concentrations used in cryo-electron microscopy, Bim1 causes the compaction of yeast microtubules and induces their rapid disassembly. Our studies demonstrate structural differences between yeast and mammalian microtubules that likely underlie their differing polymerization dynamics. These differences may reflect adaptations to the demands of different cell size or range of physiological growth temperatures.
Organizational Affiliation:
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA.,Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA enogales@lbl.gov.,Department of Molecular Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA.,Department of Molecular Genetics, Center for Medical Biotechnology, University of Duisburg-Essen, Essen, Germany.,Molecular and Cell Biology Graduate Program, University of California, Berkeley, Berkeley, CA.,Biophysics Graduate Group, University of California, Berkeley, Berkeley, CA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX.
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