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Research Database PMU-SQQUID

Plectin deposition at podosome rings requires myosin contractility.
Gad, A; Lach, S; Crimaldi, L; Gimona, M;
Cell Motil Cytoskeleton. 2008; 65(8): 614-625.
Originalarbeiten (Zeitschrift)


Gimona Mario


Metalloproteinase-dependent tissue invasion requires the formation of podosomes and invadopodia for localized matrix degradation. Actin cytoskeleton remodeling via Arp2/3-mediated actin polymerization is essential for podosome formation, and dynamic microtubules have an important role in maintaining podosome turnover in macrophages and osteoclasts. Little is known, however, about the involvement of the intermediate filament cytoskeleton in formation, stabilization, and turnover of podosomes. Here we show that vimentin intermediate filaments colocalize with the early sites of podosome formation at the stress fiber - focal adhesion interface in cultured vascular smooth muscle cells, but do not directly contribute to podosome formation, or stabilization. In unstimulated A7r5 cells the cytolinker protein plectin poorly colocalized with vimentin and the microdomains, but following induction by phorbol ester accumulated in the rings that surround the podosomes. In plectin-deficient A7r5 cells actin stress fiber remodelling is reduced in response to PDBu, and small podosomes remain localized at stable actin stress fibres. Pharmacological inhibition of actomyosin contractility by blebbistatin leads to an aberrant localization of podosomes away from the cell periphery and induces failure of plectin to surround the outer perimeter of these invasive adhesions. Taken together, we conclude that plectin is involved in growth and maturation of podosomes by reducing focal adhesion and stress fiber turnover, and that actomyosin-dependent contractility is required for the peripheral localization and specific deposition of plectin at the podosome rings.

Useful keywords (using NLM MeSH Indexing)



Blotting, Western

Cell Line

Cell Movement/drug effects

Cell Movement/physiology

Cytoskeleton/drug effects


Focal Adhesions/metabolism

Heterocyclic Compounds with 4 or More Rings/pharmacology

Intermediate Filaments/metabolism

Microscopy, Fluorescence

Muscle, Smooth/cytology

Muscle, Smooth/drug effects

Muscle, Smooth/metabolism



Phorbol 12,13-Dibutyrate/pharmacology



Pseudopodia/drug effects



RNA Interference



Find related publications in this database (Keywords)

smooth muscle
myosin contractility
intermediate filaments