Molecular Motor-Based Assays for Altered Nanomechanieal Function of Ca~(2+) - Regulatory Proteins in Cardiomyopathies

摘要

We propose that a thermo-electrical control system for rapid and reversible actuation of biomolecular motors and their partner filaments can also be used to study molecular mechanisms of cardiovascular diseases. We have previously used this device to evaluate the temperature-dependence of unregulated (absence of Ca~(2+)-regulatory proteins tropomyosin, α-Tm, and troponin, Tn) actin filament sliding powered by ATP-hydrolyzing myosin motors. Assays using the thermo-electric controller can also be applied to regulated thin filaments (F-actin plus α-Tm and Tn) to obtain energetic parameters and functional correlates of structural stability at the level of single filaments. This allows us not only to examine Ca~(2+)-dependent sliding of thin filaments, but also to test for altered function of clinically relevant mutations of cardiac myofilament proteins such as those identified in familial hypertrophic cardiomyopathy (FHC).