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Tropomyosins Regulate the Severing Activity of Gelsolin in Isoform-Dependent and Independent Manners.

ABSTRACT: The actin cytoskeleton fulfills numerous key cellular functions, which are tightly regulated in activity, localization, and temporal patterning by actin binding proteins. Tropomyosins and gelsolin are two such filament-regulating proteins. Here, we investigate how the effects of tropomyosins are coupled to the binding and activity of gelsolin. We show that the three investigated tropomyosin isoforms (Tpm1.1, Tpm1.12, and Tpm3.1) bind to gelsolin with micromolar or submicromolar affinities. Tropomyosin binding enhances the activity of gelsolin in actin polymerization and depolymerization assays. However, the effects of the three tropomyosin isoforms varied. The tropomyosin isoforms studied also differed in their ability to protect pre-existing actin filaments from severing by gelsolin. Based on the observed specificity of the interactions between tropomyosins, actin filaments, and gelsolin, we propose that tropomyosin isoforms specify which populations of actin filaments should be targeted by, or protected from, gelsolin-mediated depolymerization in living cells.

SUBMITTER: Kis-Bicskei N

PROVIDER: S-EPMC5984974 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Tropomyosins Regulate the Severing Activity of Gelsolin in Isoform-Dependent and Independent Manners.

Kis-Bicskei Nikolett N Bécsi Bálint B Erdődi Ferenc F Robinson Robert C RC Bugyi Beáta B Huber Tamás T Nyitrai Miklós M Talián Gábor Csaba GC

Biophysical journal 20180201 4

The actin cytoskeleton fulfills numerous key cellular functions, which are tightly regulated in activity, localization, and temporal patterning by actin binding proteins. Tropomyosins and gelsolin are two such filament-regulating proteins. Here, we investigate how the effects of tropomyosins are coupled to the binding and activity of gelsolin. We show that the three investigated tropomyosin isoforms (Tpm1.1, Tpm1.12, and Tpm3.1) bind to gelsolin with micromolar or submicromolar affinities. Tropo ...[more]

PMID: 29490240

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Dataset Information

Tropomyosins Regulate the Severing Activity of Gelsolin in Isoform-Dependent and Independent Manners.

Publications

Tropomyosins Regulate the Severing Activity of Gelsolin in Isoform-Dependent and Independent Manners.

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