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

Nikolett Kis-Bicskei, Bálint Bécsi, Ferenc Erdődi, Robert C. Robinson, Beáta Bugyi, Tamás Huber, Miklós Nyitrai, Gábor Csaba Talián

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)777-787
Number of pages11
JournalBiophysical Journal
Volume114
Issue number4
DOIs
Publication statusPublished - Feb 27 2018

ASJC Scopus subject areas

  • Biophysics

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