SALS, a WH2-Domain-Containing Protein, Promotes Sarcomeric Actin Filament Elongation from Pointed Ends during Drosophila Muscle Growth

Local actin filament formation powers the development of the signal-receiving arbor of neurons that underlies neuronal network formation. Yet, little is known about the molecules that drive these processes and may functionally connect them to the transient calcium pulses observed in restricted areas in the forming dendritic arbor. Here we demonstrate that Cordon-Bleu (Cobl)–like, an uncharacterized protein suggested to represent a very distantly related, evolutionary ancestor of the actin nucleator Cobl, despite having only a single G-actin–binding Wiskott–Aldrich syndrome protein Homology 2 (WH2) domain, massively promoted the formation of F-actin–rich membrane ruffles of COS-7 cells and of dendritic branches of neurons. Cobl-like hereby integrates WH2 domain functions with those of the F-actin–binding protein Abp1. Cobl-like–mediated dendritic branching is dependent on Abp1 as well as on Ca2+/calmodulin (CaM) signaling and CaM association. Calcium signaling leads to a promotion of complex formation with Cobl-like’s cofactor Abp1. Thus, Ca2+/CaM control of actin dynamics seems to be a much more broadly used principle in cell biology than previously thought.

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Clustering of VASP actively drives processive, WH2 domain-mediated actin filament elongation

The EMBO Journal ◽

10.1038/emboj.2008.211 ◽

2008 ◽

Vol 27 (22) ◽

pp. 2943-2954 ◽

Cited By ~ 139

Author(s):

Dennis Breitsprecher ◽

Antje K Kiesewetter ◽

Joern Linkner ◽

Claus Urbanke ◽

Guenter P Resch ◽

...

Keyword(s):

Actin Filament ◽

Wh2 Domain

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Faculty Opinions recommendation of Clustering of VASP actively drives processive, WH2 domain-mediated actin filament elongation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1155898.615954 ◽

2009 ◽

Author(s):

Pekka Lappalainen

Keyword(s):

Actin Filament ◽

Wh2 Domain

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Mutagenetic and electron microscopy analysis of actin filament severing by Cordon-Bleu, a WH2 domain protein

Cytoskeleton ◽

10.1002/cm.21161 ◽

2014 ◽

Vol 71 (3) ◽

pp. 170-183 ◽

Cited By ~ 10

Author(s):

Yue Jiao ◽

Matt Walker ◽

John Trinick ◽

Julien Pernier ◽

Pierre Montaville ◽

...

Keyword(s):

Electron Microscopy ◽

Actin Filament ◽

Electron Microscopy Analysis ◽

Microscopy Analysis ◽

Wh2 Domain ◽

Domain Protein

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Toward an alignment of the actin molecule within the actin filament

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075981 ◽

1983 ◽

Vol 41 ◽

pp. 450-451

Author(s):

P.R. Smith ◽

W.E. Fowler ◽

U. Aebi

Keyword(s):

Actin Filament ◽

Diffraction Data ◽

Quantitative Estimate ◽

Molecular Model ◽

Quantitative Comparison ◽

Regulatory Proteins ◽

Essential Information ◽

X Ray ◽

Maximum Resolution ◽

Lack Of Information

An understanding of the specific interactions of actin with regulatory proteins has been limited by the lack of information about the structure of the actin filament. Molecular actin has been studied in actin-DNase I complexes by single crystal X-ray analysis, to a resolution of about 0.6nm, and in the electron microscope where two dimensional actin sheets have been reconstructed to a maximum resolution of 1.5nm. While these studies have shown something of the structure of individual actin molecules, essential information about the orientation of actin in the filament is still unavailable.The work of Egelman & DeRosier has, however, suggested a method which could be used to provide an initial quantitative estimate of the orientation of actin within the filament. This method involves the quantitative comparison of computed diffraction data from single actin filaments with diffraction data derived from synthetic filaments constructed using the molecular model of actin as a building block. Their preliminary work was conducted using a model consisting of two juxtaposed spheres of equal size.

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The 3-Dimensional Molecular Structure of the Actin Filament Revisited

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119223 ◽

1985 ◽

Vol 43 ◽

pp. 480-481

Author(s):

U. Aebi ◽

R. Millonig ◽

H. Salvo

Keyword(s):

Actin Filament ◽

Supramolecular Assembly ◽

Specimen Preparation ◽

X Ray Diffraction ◽

Single Filament ◽

X Ray ◽

3 Dimensional ◽

Filament Diameter ◽

Preparation Conditions ◽

Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

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