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dc.contributor.authorKoestler, Stefan A
dc.contributor.authorRottner, Klemens
dc.contributor.authorLai, Frank
dc.contributor.authorBlock, Jennifer
dc.contributor.authorVinzenz, Marlene
dc.contributor.authorSmall, J Victor
dc.date.accessioned2009-06-16T13:02:06Z
dc.date.available2009-06-16T13:02:06Z
dc.date.issued2009
dc.identifier.citationF- and G-actin concentrations in lamellipodia of moving cells. 2009, 4 (3):e4810 PLoS ONEen
dc.identifier.issn1932-6203
dc.identifier.pmid19277198
dc.identifier.doi10.1371/journal.pone.0004810
dc.identifier.urihttp://hdl.handle.net/10033/70575
dc.description.abstractCells 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.isoenen
dc.titleF- and G-actin concentrations in lamellipodia of moving cells.en
dc.typeArticleen
dc.contributor.departmentInstitute of Molecular Biotechnology, Austrian Academy of Sciences, Vienna, Austria.en
dc.identifier.journalPloS oneen
refterms.dateFOA2018-06-13T19:44:32Z
html.description.abstractCells 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.


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