HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 3, 1948-1955, January 19, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/3/1948    most recent M610262200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Khaire, N. Articles by Noegel, A. A. Search for Related Content PubMed PubMed Citation Articles by Khaire, N. Articles by Noegel, A. A. Social Bookmarking                      What's this?

Filamin-regulated F-actin Assembly Is Essential for Morphogenesis and Controls Phototaxis in Dictyostelium^*

Nandkumar Khaire, Rolf Müller, Rosemarie Blau-Wasser, Ludwig Eichinger, Michael Schleicher, Matthias Rief^¶, Tad A. Holak^||, and Angelika A. Noegel¹

From the Institut für Biochemie I, Zentrum Molekulare Medizin Köln, Medizinische Fakultät, Universität zu Köln, 50931 Köln, Germany, the Institut für Zellbiologie, Ludwig-Maximilians-Universität, 80336 München, Germany, ^¶Physik-Department E22, Technische Universität München, James-Frank-Strasse, 85747 Garching, Germany, and the ^||Max-Planck Institut für Biochemie, 82152 Martinsried, Germany

Dictyostelium strains lacking the F-actin cross-linking protein filamin (ddFLN) have a severe phototaxis defect at the multicellular slug stage. Filamins are rod-shaped homodimers that cross-link the actin cytoskeleton into highly viscous, orthogonal networks. Each monomer chain of filamin is comprised of an F-actin-binding domain and a rod domain. In rescue experiments only intact filamin re-established correct phototaxis in filamin minus mutants, whereas C-terminally truncated filamin proteins that had lost the dimerization domain and molecules lacking internal repeats but retaining the dimerization domain did not rescue the phototaxis defect. Deletion of individual rod repeats also changed their subcellular localization, and mutant filamins in general were less enriched at the cell cortex as compared with the full-length protein and were increasingly present in the cytoplasm. For correct phototaxis ddFLN is only required at the tip of the slug because expression under control of the cell type-specific extracellular-matrix protein A (ecmA) promoter and mixing experiments with wild type cells supported phototactic orientation. Likewise, in chimeric slugs wild type cells were primarily found at the tip of the slug, which acts as an organizer in Dictyostelium morphogenesis.

Received for publication, November 2, 2006

^* This work was supported by the Deutsche Forschungsgemeinschaft, SFB 413, Köln Fortune, and the Fonds der Chemischen Industrie. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ To whom correspondence should be addressed: Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Köln, Germany. Tel.: 49-221-4786980; Fax: 49-221-4786979; E-mail: noegel{at}uni-koeln.de.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?