Tropomyosin Must Interact Weakly with Actin to Effectively Regulate Thin Filament Function.

ABSTRACT: Elongated tropomyosin, associated with actin-subunits along the surface of thin filaments, makes electrostatic interactions with clusters of conserved residues, K326, K328, and R147, on actin. The association is weak, permitting low-energy cost regulatory movement of tropomyosin across the filament during muscle activation. Interestingly, acidic D292 on actin, also evolutionarily conserved, lies adjacent to the three-residue cluster of basic amino acids and thus may moderate the combined local positive charge, diminishing tropomyosin-actin interaction and facilitating regulatory-switching. Indeed, charge neutralization of D292 is connected to muscle hypotonia in individuals with D292V actin mutations and linked to congenital fiber-type disproportion. Here, the D292V mutation may predispose

SUBMITTER: Rynkiewicz MJ 

PROVIDER: S-EPMC5768522 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature