Tadato Nagane

The Difference in Phosphorylation of Desmin and Myosin Light Chain 2 in the Bio14.6 Cardiomyopathic Heart

Desmin is one of the intermediate filaments and is important to maintain cell integrity. To investigate the function and regulation of desmin in hypertrophic cardiomyopathic hearts, we determined the content of desmin and measured the change of phosphorylation of desmin and myosin light chain 2 (MLC2) in the Biol4.6 cardiomyopathic hamster at 23 weeks of age by two-dimensional electrophoresis. The content of desmin and phosphorylated desmin was increased significandy in Biol4.6 compared to that of controls. On the other hand, MLC2 was decreased. The decline of phosphorylated MLC2, which attenuates Ca2+ sensitivity, seems to be a significant mechanism of hypertrophic cardiomyopathy. Considering the fact that phosphorylation of desmin leads to a disassembly of desmin filament and that dephosphorylation induces formation of it, this result strongly suggested that accumulated phosphorylated desmin might relate to disruption of muscle architecture, weakness, and degeneration of cardiomyocytes.