Open Collections

Description

Abstract

Sarcoplasmic reticulum (SR) Ca2+ leak is elevated in many myopathies, but whether Ca2+ leak is a driver or consequence of the disease process is not always clear. The Ryanodine Receptor, RYR1, is the SR Ca2+ release channel required for both muscle contraction and Ca2+ leak. SPEG (striated muscle preferentially expressed protein kinase) regulates the Ca2+ leak properties of RYR1 by phosphorylation of serine 2902. 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.

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.