Microtubules Coordinate Myosin Activation Zone during Cytokinesis

Researchers at the University of Washington, led by V.E. Foe, have made significant discoveries about the role of microtubules in the process of cytokinesis, the final stage of cell division. Recent research published in the Journal of Cell Biology reveals that microtubules, specifically their stability and dynamics, play a crucial role in focusing myosin activation to the cell equator, thereby contributing to the formation of the cytokinetic furrow. The study found that both stable and dynamic microtubules are essential for precise localization of myosin activation, with dynamic microtubules facilitating the recruitment of myosin to the equator.

Key Takeaways:

• Microtubules, specifically their stability and dynamics, are crucial for the formation of the cytokinetic furrow during cytokinesis.
• The study found that cortical pRLC was globally depressed before cytokinesis, then elevated only at the equator, implicating cell cycle biochemistry in pRLC depression.
• The presence of microtubules, particularly dynamic ones, is necessary for the localization of myosin activation to the equator.
• The researchers concluded that opposite effects of stable versus dynamic microtubules focus myosin activation to the cell equator during cytokinesis.
• V.E. Foe and colleagues used echinoderm zygotes to study myosin II activation in response to precise timed drug treatments.
• The study used nocodazole treatment to reveal a population of stable astral microtubules formed during anaphase, which grew longer and coincided with cortical pRLC accumulation.
• Colchicine treatment was used to shrink the mitotic apparatus, revealing pRLC suppression near dynamic microtubule arrays.

Statistics:

• The study was published in the Journal of Cell Biology in an article titled "Stable and dynamic microtubules coordinately shape the myosin activation zone during cytokinetic furrow formation."
• The article was published in volume 183, issue 3, on pages 457-470 in 2008.
• The study involved the use of echinoderm zygotes, which were treated with precise timed drug treatments to assess serine19-phosphorylated regulatory light chain (pRLC) localization.
• The researchers found that cortical pRLC was globally depressed before cytokinesis and elevated only at the equator.
• Nocodazole treatment revealed a population of stable astral microtubules, which formed during anaphase and grew longer at the equator.

Sources:

• Foe, V.E., et al. (2008). Stable and dynamic microtubules coordinately shape the myosin activation zone during cytokinetic furrow formation. Journal of Cell Biology, 183(3), 457-470.
• University of Washington, Center Cell Dynamics, Friday Harbor, WA 98250, USA.
• Rockefeller University Press, 1114 First Avenue, 4TH FL, New York, NY 10021, USA.