F- and G-actin concentrations in lamellipodia of moving cells
| Autor: | Frank P. L. Lai, J. Victor Small, Marlene Vinzenz, Jennifer Block, Klemens Rottner, Stefan A. Koestler |
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| Přispěvatelé: | Institute of Molecular Biotechnology, Austrian Academy of Sciences, Vienna, Austria. |
| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
Recombinant Fusion Proteins
Science Green Fluorescent Proteins Melanoma Experimental macromolecular substances Protein filament Mice Biopolymers Cell Movement Cell Line Tumor Cell Biology/Cytoskeleton Animals Pseudopodia Actin Photobleaching Multidisciplinary Chemistry Fluorescence recovery after photobleaching Chemical Biology/Chemical Biology of the Cell Actin cytoskeleton Actins Neoplasm Proteins Cell biology Actin Cytoskeleton Microscopy Electron Treadmilling Biochemistry/Macromolecular Assemblies and Machines Polymerization Biophysics Melanocytes Medicine Lamellipodium Research Article |
| Zdroj: | PLoS ONE, Vol 4, Iss 3, p e4810 (2009) PLoS ONE |
| Popis: | Cells protrude by polymerizing monomeric (G) into polymeric (F) actin at the tip of the lamellipodium. Actin filaments are depolymerized towards the rear of the lamellipodium in a treadmilling process, thereby supplementing a G-actin pool for a new round of polymerization. In this scenario the concentrations of F- and G-actin are principal parameters, but have hitherto not been directly determined. By comparing fluorescence intensities of bleached and unbleached regions of lamellipodia in B16-F1 mouse melanoma cells expressing EGFP-actin, before and after extraction with Triton X-100, we show that the ratio of F- to G-actin is 3.2+/-0.9. Using electron microscopy to determine the F-actin content, this ratio translates into F- and G-actin concentrations in lamellipodia of approximately 500 microM and 150 microM, respectively. The excess of G-actin, at several orders of magnitude above the critical concentrations at filament ends indicates that the polymerization rate is not limited by diffusion and is tightly controlled by polymerization/depolymerization modulators. |
| Databáze: | OpenAIRE |
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