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

Biophysical Journal
Nikolett Kis-BicskeiGábor C Talián

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.

Citations

May 6, 2019·Journal of Muscle Research and Cell Motility·Dietmar J MansteinPeter W Gunning
Oct 10, 2020·Frontiers in Molecular Biosciences·Réka PintérBeáta Bugyi
Dec 12, 2020·The Journal of Biological Chemistry·Venukumar VemulaAlf Månsson
Oct 22, 2019·Seminars in Cell & Developmental Biology·Edna C HardemanPeter W Gunning
Mar 25, 2021·Translational Oncology·Rahul Suresh, Roberto J Diaz
May 5, 2021·Proceedings of the National Academy of Sciences of the United States of America·Shlomi BrielleAmnon Buxboim

❮ Previous
Next ❯

Methods Mentioned

BETA
protein assay
gel filtration
surface-Plasmon-resonance
chip
chips
electrophoresis
fluorescence

Software Mentioned

GeneTools
BIAevaluation
Excel

Related Concepts

Related Feeds

Actin-binding Proteins

Actin-binding proteins are a component of the actin cytoskeleton that play essential roles in cellular functions such as regulation of actin polymerization, maintenance of cell polarity, gene expression regulation, cell motility and many more functions. Discover the latest research on actin-binding proteins here.