Distinct actin-tropomyosin cofilament populations drive the functional diversification of cytoskeletal myosin motor complexes

Theresia Reindl; Sven Giese; Johannes N Greve; Patrick Y Reinke; Igor Chizhov; Sharissa L Latham; Daniel P Mulvihill; Manuel H Taft; Dietmar J Manstein

doi:10.1016/j.isci.2022.104484

Distinct actin-tropomyosin cofilament populations drive the functional diversification of cytoskeletal myosin motor complexes

iScience. 2022 May 30;25(7):104484. doi: 10.1016/j.isci.2022.104484. eCollection 2022 Jul 15.

Authors

Affiliations

¹ Institute for Biophysical Chemistry, Fritz-Hartmann-Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany.
² School of Biosciences, University of Kent, CT2 7NJ Canterbury, UK.
³ Division for Structural Biochemistry, Hannover Medical School, 30625 Hannover, Germany.
⁴ RESiST, Cluster of Excellence 2155, Medizinische Hochschule Hannover, 30625 Hannover, Germany.

Abstract

The effects of N-terminal acetylation of the high molecular weight tropomyosin isoforms Tpm1.6 and Tpm2.1 and the low molecular weight isoforms Tpm1.12, Tpm3.1, and Tpm4.2 on the actin affinity and the thermal stability of actin-tropomyosin cofilaments are described. Furthermore, we show how the exchange of cytoskeletal tropomyosin isoforms and their N-terminal acetylation affects the kinetic and chemomechanical properties of cytoskeletal actin-tropomyosin-myosin complexes. Our results reveal the extent to which the different actin-tropomyosin-myosin complexes differ in their kinetic and functional properties. The maximum sliding velocity of the actin filament as well as the optimal motor density for continuous unidirectional movement, parameters that were previously considered to be unique and invariant properties of each myosin isoform, are shown to be influenced by the exchange of the tropomyosin isoform and the N-terminal acetylation of tropomyosin.

Keywords: Biochemistry; Biological sciences; Biomolecules; Biophysics; Protein.