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Updated: Aug 19, 2025

Myo-mechanical Analysis of Isolated Skeletal Muscle
Published on: February 22, 2011
Pseudo-phosphorylation of essential light chains affects the functioning of skeletal muscle myosin
Daria S Yampolskaya1, Galina V Kopylova2, Daniil V Shchepkin2
1Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky prosp. 33, Moscow 119071, Russia.
Abstract:
The work aimed to investigate how the phosphorylation of the myosin essential light chain of fast skeletal myosin (LC1) affects the functional properties of the myosin molecule. Using mass-spectrometry, we revealed phosphorylated peptides of LC1 in myosin from different fast skeletal muscles. Mutations S193D and T65D that mimic natural phosphorylation of LC1 were produced, and their effects on functional properties of the entire myosin molecule and isolated myosin head (S1) were studied. We have shown that T65D mutation drastically decreased the sliding velocity of thin filaments in an in vitro motility assay and strongly increased the duration of actin-myosin interaction in optical trap experiments. These effects of T65D mutation in LC1 observed only with the whole myosin but not with S1 were prevented by double T65D/S193D mutation. The T65D and T65D/S193D mutations increased actin-activated ATPase activity of S1 and decreased ADP affinity for the actin-S1 complex. The results indicate that pseudo-phosphorylation of LC1 differently affects the properties of the whole myosin molecule and its isolated head. Also, the results show that phosphorylation of LC1 of skeletal myosin could be one more mechanism of regulation of actin-myosin interaction that needs further investigation.
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