F- and G-actin concentrations in lamellipodia of moving cells.

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 conce...

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Autores principales: Stefan A Koestler, Klemens Rottner, Frank Lai, Jennifer Block, Marlene Vinzenz, J Victor Small
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Publicado: Public Library of Science (PLoS) 2009
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Acceso en línea:https://doaj.org/article/d3f0e5841f53414aa39c4a8c4644f16e
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spelling oai:doaj.org-article:d3f0e5841f53414aa39c4a8c4644f16e2021-11-25T06:16:46ZF- and G-actin concentrations in lamellipodia of moving cells.1932-620310.1371/journal.pone.0004810https://doaj.org/article/d3f0e5841f53414aa39c4a8c4644f16e2009-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/19277198/?tool=EBIhttps://doaj.org/toc/1932-6203Cells 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.Stefan A KoestlerKlemens RottnerFrank LaiJennifer BlockMarlene VinzenzJ Victor SmallPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 4, Iss 3, p e4810 (2009)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Stefan A Koestler
Klemens Rottner
Frank Lai
Jennifer Block
Marlene Vinzenz
J Victor Small
F- and G-actin concentrations in lamellipodia of moving cells.
description 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.
format article
author Stefan A Koestler
Klemens Rottner
Frank Lai
Jennifer Block
Marlene Vinzenz
J Victor Small
author_facet Stefan A Koestler
Klemens Rottner
Frank Lai
Jennifer Block
Marlene Vinzenz
J Victor Small
author_sort Stefan A Koestler
title F- and G-actin concentrations in lamellipodia of moving cells.
title_short F- and G-actin concentrations in lamellipodia of moving cells.
title_full F- and G-actin concentrations in lamellipodia of moving cells.
title_fullStr F- and G-actin concentrations in lamellipodia of moving cells.
title_full_unstemmed F- and G-actin concentrations in lamellipodia of moving cells.
title_sort f- and g-actin concentrations in lamellipodia of moving cells.
publisher Public Library of Science (PLoS)
publishDate 2009
url https://doaj.org/article/d3f0e5841f53414aa39c4a8c4644f16e
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AT jenniferblock fandgactinconcentrationsinlamellipodiaofmovingcells
AT marlenevinzenz fandgactinconcentrationsinlamellipodiaofmovingcells
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