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
Affiliations
Theresia Reindl
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Sven Giese
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Johannes N. Greve
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Patrick Y. Reinke
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Igor Chizhov
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Sharissa L. Latham
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Daniel P. Mulvihill
School of Biosciences, University of Kent, CT2 7NJ Canterbury, UK
Manuel H. Taft
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany
Dietmar J. Manstein
Institute for Biophysical Chemistry, Fritz–Hartmann–Centre for Medical Research, Hannover Medical School, 30625 Hannover, Germany; Division for Structural Biochemistry, Hannover Medical School, 30625 Hannover, Germany; RESiST, Cluster of Excellence 2155, Medizinische Hochschule Hannover, 30625 Hannover, Germany; Corresponding author
Summary: 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.
