Cardiac troponin and tropomyosin bind to F-actin cooperatively, as revealed by fluorescence microscopy.

ABSTRACT: In cardiac muscle, binding of troponin (Tn) and tropomyosin (Tpm) to filamentous (F)-actin forms thin filaments capable of Ca²⁺ -dependent regulation of contraction. Tpm binds to F-actin in a head-to-tail fashion, while Tn stabilizes these linkages. Valuable structural and functional information has come from biochemical, X-ray, and electron microscopy data. However, the use of fluorescence microscopy to study thin filament assembly remains relatively underdeveloped. Here, triple fluorescent labeling of Tn, Tpm, and F-actin allowed us to track thin filament assembly by fluorescence microscopy. It is shown here that Tn and Tpm molecules self-organize on actin filaments and give rise to decorated and undecorated regions. Binding curves based on colocalization of Tn and Tpm on F-ac

SUBMITTER: Solis C 

PROVIDER: S-EPMC7327902 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature