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A functional link between dynamin and the actin cytoskeleton at podosomes
G C Ochoa1, V I Slepnev, L Neff
1Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
The Journal of Cell Biology
|July 26, 2000
Summary
Dynamin, a protein involved in membrane dynamics, is present at podosomes, crucial cell adhesion sites. This study reveals dynamin
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cell transformation alters cell-substratum adhesion structures.
- Podosomes, dot-like attachment sites rich in actin, characterize transformed cells and certain motile cells like osteoclasts.
- Podosomes feature tubular plasma membrane invaginations, similar to those formed by dynamin.
Purpose of the Study:
- To investigate the presence and function of dynamin at podosomes.
- To explore the relationship between dynamin and actin dynamics within podosomes.
Main Methods:
- Immunodetection of dynamin 2 and endophilin 2 at podosomes.
- Expression of GFP-tagged dynamin 2 variants in cells.
- Fluorescence recovery after photobleaching (FRAP) to assess protein turnover.
- Analysis of podosome structure and actin dynamics upon expression of dynamin mutants.
Main Results:
- Dynamin 2 and its binding partner endophilin 2 are localized to podosomes in transformed cells and osteoclasts.
- Wild-type dynamin 2 efficiently targets podosomes and exhibits rapid turnover with actin.
- A dynamin 2 mutant (G273D) disrupts podosome formation, while another (K44A) affects actin turnover at podosomes.
Conclusions:
- Dynamin plays a functional role in the dynamics of actin-based attachment sites (podosomes).
- This study establishes a link between dynamin family proteins and the regulation of cell-substratum adhesion structures.