In anaphase, the spindle dictates the site of contractile ring assembly. Assembly and ingression of the contractile ring involves activation of myosin-II and actin polymerization, which are triggered by the GTPase RhoA. In many cells, the central spindle affects division plane positioning via unknown molecular mechanisms. Here, we dissect furrow formation in human cells and show that the RhoGEF ECT2 is required for cortical localization of RhoA and contractile ring assembly. ECT2 concentrates on the central spindle by binding to centralspindlin. Depletion of the centralspindlin component MKLP1 prevents central spindle localization of ECT2; however, RhoA, F-actin, and myosin still accumulate on the equatorial cell cortex. Depletion of the other centralspindlin component, CYK-4/MgcRacGAP, prevents cortical accumulation of RhoA, F-actin, and myosin. CYK-4 and ECT2 interact, and this interaction is cell cycle regulated via ECT2 phosphorylation. Thus, central spindle localization of ECT2 assists division plane positioning and the CYK-4 subunit of centralspindlin acts upstream of RhoA to promote furrow assembly.
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15 August 2005
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August 15 2005
An ECT2–centralspindlin complex regulates the localization and function of RhoA
Özlem Yüce,
Özlem Yüce
Research Institute of Molecular Pathology, 1030 Vienna, Austria
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Alisa Piekny,
Alisa Piekny
Research Institute of Molecular Pathology, 1030 Vienna, Austria
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Michael Glotzer
Michael Glotzer
Research Institute of Molecular Pathology, 1030 Vienna, Austria
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Özlem Yüce
Research Institute of Molecular Pathology, 1030 Vienna, Austria
Alisa Piekny
Research Institute of Molecular Pathology, 1030 Vienna, Austria
Michael Glotzer
Research Institute of Molecular Pathology, 1030 Vienna, Austria
Correspondence to Michael Glotzer: [email protected]
Ö. Yüce and A. Piekny contributed equally to this paper.
A. Piekny and M. Glotzer's present address is Dept. of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637.
Abbreviations used in this paper: BRCT, BRCA1 COOH terminus; CBD, chitin binding domain; GAP, GTPase activating protein; GEF, guanine nucleotide exchange factor; LatA, Latrunculin A.
Received:
January 26 2005
Accepted:
July 13 2005
Online ISSN: 1540-8140
Print ISSN: 0021-9525
The Rockefeller University Press
2005
J Cell Biol (2005) 170 (4): 571–582.
Article history
Received:
January 26 2005
Accepted:
July 13 2005
Citation
Özlem Yüce, Alisa Piekny, Michael Glotzer; An ECT2–centralspindlin complex regulates the localization and function of RhoA . J Cell Biol 15 August 2005; 170 (4): 571–582. doi: https://doi.org/10.1083/jcb.200501097
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