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Physical Limits on the Precision of Mitotic Spindle Positioning by Microtubule Pushing forces
Author(s) -
Howard Jonathon,
GarzonCoral Carlos
Publication year - 2017
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.201700122
Subject(s) - astral microtubules , microtubule , spindle pole body , spindle apparatus , mitosis , cell cortex , dynein , biophysics , physics , cell division , microbiology and biotechnology , biology , cytoskeleton , cell , genetics
Tissues are shaped and patterned by mechanical and chemical processes. A key mechanical process is the positioning of the mitotic spindle, which determines the size and location of the daughter cells within the tissue. Recent force and position‐fluctuation measurements indicate that pushing forces, mediated by the polymerization of astral microtubules against the cell cortex, maintain the mitotic spindle at the cell center in Caenorhabditis elegans embryos. The magnitude of the centering forces suggests that the physical limit on the accuracy and precision of this centering mechanism is determined by the number of pushing microtubules rather than by thermally driven fluctuations. In cells that divide asymmetrically, anti‐centering, pulling forces generated by cortically located dyneins, in conjunction with microtubule depolymerization, oppose the pushing forces to drive spindle displacements away from the center. Thus, a balance of centering pushing forces and anti‐centering pulling forces localize the mitotic spindles within dividing C. elegans cells.