Of bars and rings : Hof1-dependent cytokinesis in multiseptated hyphae of Ashbya gossypii

Kaufmann, A. and Philippsen, P.. (2009) Of bars and rings : Hof1-dependent cytokinesis in multiseptated hyphae of Ashbya gossypii. Molecular and cellular biology, Vol. 29, H. 3. pp. 771-783.

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Official URL: http://edoc.unibas.ch/dok/A5257584

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We analyzed the development of multiple septa in elongated multinucleated cells (hyphae) of the filamentous ascomycete Ashbya gossypii in which septation is apparently uncoupled from nuclear cycles. A key player for this compartmentalization is the PCH protein Hof1. Hyphae that are lacking this protein form neither actin rings nor septa but still elongate at wild-type speed. Using in vivo fluorescence microscopy, we present for the first time the coordination of cytokinesis and septation in multiseptated and multinucleated cells. Hof1, the type II myosin Myo1, the landmark protein Bud3, and the IQGAP Cyk1 form collars of cortical bars already adjacent to hyphal tips, thereby marking the sites of septation. While hyphae continue to elongate, these proteins gradually form cortical rings. This bar-to-ring transition depends on Hof1 and Cyk1 but not Myo1 and is required for actin ring assembly. The Fes/CIP4 homology (FCH) domain of Hof1 ensures efficient localization of Hof1, whereas ring integrity is conferred by the Src homology 3 (SH3) domain. Up to several hours after site selection, actin ring contraction leads to membrane invagination and subsequent cytokinesis. Simultaneously, a septum forms between the adjacent hyphal compartments, which do not separate. During evolution, A. gossypii lost the homologs of two enzymes essential for cell separation in Saccharomyces cerevisiae.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Applied Microbiology (Philippsen)
UniBasel Contributors:Philippsen, Peter
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Society for Microbiology
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:20
Deposited On:22 Mar 2012 13:18

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