Regulation of Ca2+ leak and susceptibility to malignant hyperthermia and heat stroke

Mutation of Serine S2902 to an aspartic acid to mimic SPEG phosphorylation of RYR1 decreases muscle temperature-dependent SR Ca2+ leak, restores the levels of excitation-contraction coupling proteins, and reduces the heat and volatile anesthetic sensitivity of mice with a malignant hyperthermia susceptibility mutation in RYR1 (Y524S, Y522S in humans). The S2902D mice allow a direct test of the role of SR Ca2+ leak in both normal muscle function (aging, exercise) and mice disease pathophysiology.

Methods

Analysis of phosphoylation sites on RYR1 by immunoprecipitation, mass spectrometry, and parallel reaction monitoring of gastrocnemius muscle for floxed controls (FL) and SPEG-deficient mice (SPEG KO) data were plotted as log2(fold change) versus -log(q), where q is the false discovery rate. Other techniques include force with force transducers, Western blots, and indirect calorimetry, as described in the method.