A new twist on tropomyosin binding to actin filaments: perspectives on thin filament function, assembly and biomechanics.

ABSTRACT: Tropomyosin, best known for its role in the steric regulation of muscle contraction, polymerizes head-to-tail to form cables localized along the length of both muscle and non-muscle actin-based thin filaments. In skeletal and cardiac muscles, tropomyosin, under the control of troponin and myosin, moves in a cooperative manner between blocked, closed and open positions on filaments, thereby masking and exposing actin-binding sites necessary for myosin crossbridge head interactions. While the coiled-coil signature of tropomyosin appears to be simple, closer inspection reveals surprising structural complexity required to perform its role in steric regulation. For example, component α-helices of coiled coils are typically zippered together along a continuous core hydrophobic stripe. Tropomyosi

SUBMITTER: Lehman W 

PROVIDER: S-EPMC6697252 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature