title: Dynacortin contributes to cortical viscoelasticity and helps define the shape changes of cytokinesis.
abstract: 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.
authors.affiliation: Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Kristine D
authors.initials: KD
authors.lastname: Girard
authors.forename: Charles
authors.initials: C
authors.lastname: Chaney
authors.forename: Michael
authors.initials: M
authors.lastname: Delannoy
authors.forename: Scot C
authors.initials: SC
authors.lastname: Kuo
authors.forename: Douglas N
authors.initials: DN
authors.lastname: Robinson
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D048430:Cell Shape; D048749:Cytokinesis / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D004023:Dictyostelium / Q000166:cytology / Q000378:metabolism; D004548:Elasticity; D007834:Lasers; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012212:Rheology / Q000379:methods
chemical_list: D000199:Actins; D018797:Cell Cycle Proteins; D008840:Microfilament Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C101109:ctxA protein, Dictyostelium discoideum; C413645:dct protein, Dictyostelium discoideum