Lane 1, control myocardium; lane 2, gelsolin-treated myocardium; lane 3, actin filament-reconstituted myocardium; lane 4, Tm-reconstituted myocardium; lane 5, Tm–Tn-reconstituted myocardium. The Tm-reconstituted myocardium (lane 4) was first treated with gelsolin, then actin filament was reconstituted before Tm was reconstituted. The Tm–Tn-reconstituted myocardium (lane 5) was first treated with gelsolin, then actin filament was reconstituted, followed by sequential reconstitution of Tm and Tn. In lane 2, gelsolin is visible just below the α-actinin band. Lane 1 is from one gel, and lanes 2–5 are from another gel with a different order. Abbreviations: MHC, myosin heavy chain; Tm, tropomyosin; TnT, troponin T; TnI, troponin I; MLC1, myosin light chain 1; MLC2, myosin light chain 2.