Architectural dynamics and gene replacement of coronin suggest its role in cytokinesis.
Coronin is a ubiquitous actin-binding protein representing a member of proteins portraying a WD-repeat sequence, including the beta-subunits of trimeric G-proteins. Coronin has been suggested to participate in multiple, actin-based physiological activities such as cell movement and cell division. Although the slow growth of coronin deletion mutants has been attributed to a defect in the fluid-phase uptake of nutrients, the exact role of coronin in cytoskeletal organization has not been elucidated. In this study, we examined a role of coronin in cytokinesis by analyzing the effect of coronin deletion on the actin cytoskeleton and its dynamic distribution using a green fluorescent protein (GFP)-coronin fusion protein. We show that GFP-coronin works similarly to natural coronin in vivo and in vitro. In live cells, GFP-coronin was found to accumulate into the cleavage furrow during cytokinesis. The fluorescence pattern suggests its association to the contractile ring throughout cytokinesis. Interestingly, a substantial amount of coronin was also bound to F-actin at the prospective posterior cortex of the daughter cells. We also show that the coronin null cells reveal irregularities in organization of actin and myosin II and divide by a process identical to the traction-mediated cytofission reported in myosin II mutants. Overall, this study suggests that coronin is essential for organizing the normal actin cytoskeleton and plays a significant role in cell division.
Fukui
Y
Y
Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611-3008, USA. y-fukui@nwu.edu
Engler
S
S
Inoué
S
S
de Hostos
E L
EL
D000199:Actins / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002455:Cell Division / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics / Q000254:growth & development; D049452:Green Fluorescent Proteins; D006639:Histidine / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008215:Lymphocytes, Null; D008840:Microfilament Proteins / Q000235:genetics / Q000502:physiology*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D009218:Myosins / Q000378:metabolism; D010641:Phenotype; D013997:Time Factors
D000199:Actins; D008164:Luminescent Proteins; D008840:Microfilament Proteins; C072061:coronin proteins; D049452:Green Fluorescent Proteins; D006639:Histidine; D009218:Myosins