F- and G-actin concentrations in lamellipodia of moving cells.
dc.contributor.author | Koestler, Stefan A | |
dc.contributor.author | Rottner, Klemens | |
dc.contributor.author | Lai, Frank | |
dc.contributor.author | Block, Jennifer | |
dc.contributor.author | Vinzenz, Marlene | |
dc.contributor.author | Small, J Victor | |
dc.date.accessioned | 2009-06-16T13:02:06Z | |
dc.date.available | 2009-06-16T13:02:06Z | |
dc.date.issued | 2009 | |
dc.identifier.citation | F- and G-actin concentrations in lamellipodia of moving cells. 2009, 4 (3):e4810 PLoS ONE | en |
dc.identifier.issn | 1932-6203 | |
dc.identifier.pmid | 19277198 | |
dc.identifier.doi | 10.1371/journal.pone.0004810 | |
dc.identifier.uri | http://hdl.handle.net/10033/70575 | |
dc.description.abstract | 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. | |
dc.language.iso | en | en |
dc.title | F- and G-actin concentrations in lamellipodia of moving cells. | en |
dc.type | Article | en |
dc.contributor.department | Institute of Molecular Biotechnology, Austrian Academy of Sciences, Vienna, Austria. | en |
dc.identifier.journal | PloS one | en |
refterms.dateFOA | 2018-06-13T19:44:32Z | |
html.description.abstract | 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. |