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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Auteurs principaux:	Stefan A Koestler, Klemens Rottner, Frank Lai, Jennifer Block, Marlene Vinzenz, J Victor Small
Format:	article
Langue:	EN
Publié:	Public Library of Science (PLoS) 2009
Sujets:	Medicine R Science Q
Accès en ligne:	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
work_keys_str_mv	AT stefanakoestler fandgactinconcentrationsinlamellipodiaofmovingcells AT klemensrottner fandgactinconcentrationsinlamellipodiaofmovingcells AT franklai fandgactinconcentrationsinlamellipodiaofmovingcells AT jenniferblock fandgactinconcentrationsinlamellipodiaofmovingcells AT marlenevinzenz fandgactinconcentrationsinlamellipodiaofmovingcells AT jvictorsmall fandgactinconcentrationsinlamellipodiaofmovingcells
_version_	1718414011985297408

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

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