UMMS Affiliation

Department of Physiology

Publication Date

10-26-2007

Document Type

Article

Subjects

Myosin Type II; Actins; Cytokinesis; Signal Transduction

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Equatorial organization of myosin II and actin has been recognized as a universal event in cytokinesis of animal cells. Current models for the formation of equatorial cortex favor either directional cortical transport toward the equator or localized de novo assembly. However, this process has never been analyzed directly in dividing mammalian cells at a high resolution. Here we applied total internal reflection fluorescence microscope (TIRF-M), coupled with spatial temporal image correlation spectroscopy (STICS) and a new analytical approach termed temporal differential microscopy (TDM), to image the dynamics of myosin II and actin during the assembly of equatorial cortex. Our results indicated distinct and at least partially independent mechanisms for the early equatorial recruitment of myosin and actin filaments. Cortical myosin showed no detectable directional flow during early cytokinesis. In addition to equatorial assembly, we showed that localized inhibition of disassembly contributed to the formation of the equatorial myosin band. In contrast to myosin, actin filaments underwent a striking flux toward the equator. Myosin motor activity was required for the actin flux, but not for actin concentration in the furrow, suggesting that there was a flux-independent, de novo mechanism for actin recruitment along the equator. Our results indicate that cytokinesis involves signals that regulate both assembly and disassembly activities and argue against mechanisms that are coupled to global cortical movements.

Rights and Permissions

Citation: Mol Biol Cell. 2008 Jan;19(1):318-26. Epub 2007 Oct 24. Link to article on publisher's site

DOI of Published Version

10.1091/mbc.E07-08-0783

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

Molecular biology of the cell

PubMed ID

17959823

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