Coiled-coil tropomyosin binds to consecutive actin-subunits along actin-containing thin filaments. Tropomyosin molecules then polymerize head-to-tail to form cables that wrap helically around the filaments. Little is known about the assembly process that leads to continuous, gap-free tropomyosin cable formation. We propose that tropomyosin molecules diffuse over the actin-filament surface to connect head-to-tail to partners. This possibility is likely because (1) tropomyosin hovers loosely over the actin-filament, thus binding weakly to F-actin and (2) low energy-barriers provide tropomyosin freedom for 1D axial translation on F-actin. We consider that these unique features of the actin-tropomyosin interaction are the basis of tropomyosin cable formation.

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continuous gapfree tropomyosin cable actintropomyosin interaction headtotail 1d axial translation on factin

Stefan Fischer,Michael J. Rynkiewicz,Jeffrey R. Moore,William Lehman,.Tropomyosin diffusion over actin subunits facilitates thin filament assembly. 3 (1),.

Stefan Fischer,Michael J. Rynkiewicz,Jeffrey R. Moore,William Lehman,"Tropomyosin diffusion over actin subunits facilitates thin filament assembly" 3

Stefan Fischer,Michael J. Rynkiewicz,Jeffrey R. Moore,William Lehman,"Tropomyosin diffusion over actin subunits facilitates thin filament assembly"