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Gelsolin mediates calcium-dependent disassembly of Listeria actin tails

Larson, Laura
Gibson, Bruce
Li, Wei
Hao, Binghua
Bamburg, J. R.
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Published in Proceedings of the National Academy of Sciences of the United States of America. 2005, vol. 102, no. 6, p. 1921-1926
Abstract The role of intracellular Ca2+ in the regulation of actin filament assembly and disassembly has not been clearly defined. We show that reduction of intracellular free Ca2+ concentration ([Ca2+]i) to <40 nM in Listeria monocytogenes-infected, EGFP-actin-transfected Madin-Darby canine kidney cells results in a 3-fold lengthening of actin filament tails. This increase in tail length is the consequence of marked slowing of the actin filament disassembly rate, without a significant change in assembly rate. The Ca2+-sensitive actin-severing protein gelsolin concentrates in the Listeria rocket tails at normal resting [Ca2+]i and disassociates from the tails when [Ca2+]i is lowered. Reduction in [Ca2+]i also blocks the severing activity of gelsolin, but not actin-depolymerizing factor (ADF)/cofilin microinjected into Listeria-infected cells. In Xenopus extracts, Listeria tail lengths are also calcium-sensitive, markedly shortening on addition of calcium. Immunodepletion of gelsolin, but not Xenopus ADF/cofilin, eliminates calcium-sensitive actin-filament shortening. Listeria tail length is also calcium-insensitive in gelsolin-null mouse embryo fibroblasts. We conclude that gelsolin is the primary Ca2+-sensitive actin filament recycling protein in the cell and is capable of enhancing Listeria actin tail disassembly at normal resting [Ca2+]i (145 nM). These experiments illustrate the unique and complementary functions of gelsolin and ADF/cofilin in the recycling of actin filaments.
Keywords Actin Depolymerizing FactorsActins/genetics/ metabolismAnimalsCalcium/ metabolismCells, CulturedChelating Agents/metabolismEgtazic Acid/ analogs & derivatives/metabolismFocal Adhesion Kinase 1Focal Adhesion Protein-Tyrosine KinasesGelsolin/ metabolismListeria monocytogenes/cytology/ metabolismMiceMice, KnockoutMicrofilament Proteins/metabolismProtein-Tyrosine Kinases/genetics/metabolismRecombinant Fusion Proteins/genetics/metabolismXenopus laevis
PMID: 15671163
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LARSON, Laura et al. Gelsolin mediates calcium-dependent disassembly of Listeria actin tails. In: Proceedings of the National Academy of Sciences of the United States of America, 2005, vol. 102, n° 6, p. 1921-1926. doi: 10.1073/pnas.0409062102 https://archive-ouverte.unige.ch/unige:7399

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Deposited on : 2010-06-21

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