This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kaufmann, A.
Right arrow Articles by Philippsen, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kaufmann, A.
Right arrow Articles by Philippsen, P.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, February 2009, p. 771-783, Vol. 29, No. 3
0270-7306/09/$08.00+0     doi:10.1128/MCB.01150-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Of Bars and Rings: Hof1-Dependent Cytokinesis in Multiseptated Hyphae of Ashbya gossypii{triangledown} ,§

Andreas Kaufmann and Peter Philippsen*

Biozentrum der Universität Basel, Klingelbergstrasse 50-70, CH-4056 Basel, Switzerland

Received 21 July 2008/ Returned for modification 18 August 2008/ Accepted 12 November 2008

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.

* Corresponding author. Mailing address: Applied Microbiology, Biozentrum, Klingelbergsrasse 50-70, CH-4056 Basel, Switzerland. Phone: 4161 267 1480. Fax: 4161 267 1481. E-mail: peter.philippsen{at}unibas.ch

{triangledown} Published ahead of print on 24 November 2008.

§ Supplemental material for this article may be found at http://mcb.asm.org/.

Molecular and Cellular Biology, February 2009, p. 771-783, Vol. 29, No. 3
0270-7306/09/$08.00+0     doi:10.1128/MCB.01150-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»