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  • The EMBO Journal (2004) 23, 1536 - 1546
  • doi:10.1038/sj.emboj.7600167

Published online: 11 March 2004

Dynacortin contributes to cortical viscoelasticity and helps define the shape changes of cytokinesis

Kristine D Girard1, Charles Chaney2, Michael Delannoy1, Scot C Kuo2 and Douglas N Robinson1

  1. Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
  2. Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Correspondence to:

Douglas N Robinson, Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2196, USA. Tel.: +410 502 2850; E-mail: dnr@jhmi.edu

Received 5 December 2003; Accepted 19 February 2004

During cytokinesis, global and equatorial pathways deform the cell cortex in a stereotypical manner, which leads to daughter cell separation. Equatorial forces are largely generated by myosin-II and the actin crosslinker, cortexillin-I. In contrast, global mechanics are determined by the cortical cytoskeleton, including the actin crosslinker, dynacortin. We used direct morphometric characterization and laser-tracking microrheology to quantify cortical mechanical properties of wild-type and cortexillin-I and dynacortin mutant Dictyostelium cells. Both cortexillin-I and dynacortin influence cytokinesis and interphase cortical viscoelasticity as predicted from genetics and biochemical data using purified dynacortin proteins. Our studies suggest that the regulation of cytokinesis ultimately requires modulation of proteins that control the cortical mechanical properties that establish the force-balance that specifies the shapes of cytokinesis. The combination of genetic, biochemical, and biophysical observations suggests that the cell's cortical mechanical properties control how the cortex is remodeled during cytokinesis.

  • Keywords:

    • cell morphology,
    • cortical mechanics,
    • cytokinesis,
    • Dictyostelium,
    • rheology