Whole-cell mechanical loading and unloading triggers more post-translational modifications in Z-disc proteins than myosin activators and inhibitors

The hypothesis tested is that unloading of mechanical forces affects acetylation, ubiquitination and phosphorylation of α-actinin and CapZ, which are actin-binding proteins in the Z-disc. We applied targeted proteomics to interrogate thepost-translational modification changes during loading and unloading. Cell morphology and post-translational modifications were determined in a mechanical intervention consisting of 1 Hz cyclic strain for 24 hr (loaded) followed by 6 hr rest (unloaded) of cultured neonatal rat ventricular myocytes (NRVMs).