Inhibition of Ubiquitin Proteasome System Rescues the Defective Sarco(endo)plasmic Reticulum Ca2+-ATPase (SERCA1) Protein Causing Chianina Cattle Pseudomyotonia

• Published in: The Journal of biological chemistry Vol. 289; no. 48; pp. 33073 - 33082
• Main Authors: Bianchini, Elisa, Testoni, Stefania, Gentile, Arcangelo, Calì, Tito, Ottolini, Denis, Villa, Antonello, Brini, Marisa, Betto, Romeo, Mascarello, Francesco, Nissen, Poul, Sandonà, Dorianna, Sacchetto, Roberta
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 28.11.2014; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Brody Disease; Calcium; Calcium - metabolism; Calcium ATPase; Cattle; Cattle Congenital Pseudomyotonia; Cattle Diseases - enzymology; Cattle Diseases - genetics; Cattle Diseases - pathology; Cricetinae; HEK293 Cells; Humans; Isaacs Syndrome - enzymology; Isaacs Syndrome - genetics; Isaacs Syndrome - pathology; Isaacs Syndrome - veterinary; Leupeptins - pharmacology; Molecular Bases of Disease; Muscle Proteins - genetics; Muscle Proteins - metabolism; Mutation; Proteasome; Proteasome Endopeptidase Complex - genetics; Proteasome Endopeptidase Complex - metabolism; Proteasome Inhibitors - pharmacology; Protein Folding - drug effects; Sarco(endo)plasmic Reticulum Calcium ATPase (SERCA1); Sarcoplasmic Reticulum (SR); Sarcoplasmic Reticulum - enzymology; Sarcoplasmic Reticulum - genetics; Sarcoplasmic Reticulum - pathology; Sarcoplasmic Reticulum Calcium-Transporting ATPases - genetics; Sarcoplasmic Reticulum Calcium-Transporting ATPases - metabolism; Skeletal Muscle; Ubiquitin - genetics; Ubiquitin - metabolism; Skeletal Muscle; Brody Disease; Calcium; Sarcoplasmic Reticulum (SR); Sarco(endo)plasmic Reticulum Calcium ATPase (SERCA1); Calcium ATPase; Cattle Congenital Pseudomyotonia; Proteasome
• ISSN: 0021-9258; 1083-351X; 1083-351X
• DOI: 10.1074/jbc.M114.576157

A missense mutation in ATP2A1 gene, encoding sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA1) protein, causes Chianina cattle congenital pseudomyotonia, an exercise-induced impairment of muscle relaxation. Skeletal muscles of affected cattle are characterized by a selective reduction of SERCA1 in sarcoplasmic reticulum membranes. In this study, we provide evidence that the ubiquitin proteasome system is involved in the reduced density of mutated SERCA1. The treatment with MG132, an inhibitor of ubiquitin proteasome system, rescues the expression level and membrane localization of the SERCA1 mutant in a heterologous cellular model. Cells co-transfected with the Ca2+-sensitive probe aequorin show that the rescued SERCA1 mutant exhibits the same ability of wild type to maintain Ca2+ homeostasis within cells. These data have been confirmed by those obtained ex vivo on adult skeletal muscle fibers from a biopsy from a pseudomyotonia-affected subject. Our data show that the mutation generates a protein most likely corrupted in proper folding but not in catalytic activity. Rescue of mutated SERCA1 to sarcoplasmic reticulum membrane can re-establish resting cytosolic Ca2+ concentration and prevent the appearance of pathological signs of cattle pseudomyotonia. Background: Human Brody disease and cattle pseudomyotonia are due to mutations in SERCA1. Results: Cattle pseudomyotonia SERCA1, although functional, is prematurely degraded by the ubiquitin-proteasome system; proteasome inhibition restores calcium homeostasis in a cellular model and in muscle fibers from affected cattle. Conclusion: Functional rescue of mutated SERCA1 is feasible by preventing its degradation. Significance: The data suggest a therapeutic approach against Brody disease.