Single Filament Behavior of Microtubules in the Presence of Added Divalent Counterions

Microtubules (MTs) are hollow biopolymeric filaments that function to define the shape of eukaryotic cells, serve as a platform for intracellular vesicular transport, and separate chromosomes during mitosis. One means of physiological regulation of MT mechanics and dynamics, critical to their adapta...

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Bibliographic Details
Published in:Biomacromolecules 2014-10, Vol.15 (10), p.3696-3705
Main Authors: Bouxsein, Nathan F, Bachand, George D
Format: Article
Language:English
Subjects:
Biological and medical sciences
Biological Transport - physiology
Cell structures and functions
Cytoskeleton, cytoplasm. Intracellular movements
Eukaryotic Cells - metabolism
Eukaryotic Cells - physiology
Fundamental and applied biological sciences. Psychology
Ions - metabolism
Kinesin - metabolism
Microtubules - metabolism
Mitosis - physiology
Molecular and cellular biology
Polymerization
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Summary:Microtubules (MTs) are hollow biopolymeric filaments that function to define the shape of eukaryotic cells, serve as a platform for intracellular vesicular transport, and separate chromosomes during mitosis. One means of physiological regulation of MT mechanics and dynamics, critical to their adaptability in such processes, is through electrostatics due to the strong polyelectrolyte nature of MTs. Here, we show that in the presence of physiologically relevant amounts of divalent salts, MTs experience a dramatic increase in persistence length or stiffness, which is counter to theoretical expectations and experimental observations in similar systems (e.g., DNA). Divalent salt-dependent effects on MT dynamics were also observed with respect to suppressing depolymerization as well as reducing dispersion in kinesin-driven molecular motor transport assays. These results establish a novel mechanism by which MT dynamics, mechanics, and interaction with molecular motors may be regulated by physiologically relevant concentrations of divalent salts.
ISSN:1525-7797
1526-4602
DOI:10.1021/bm500988r