Preventing phosphorylation of dystroglycan ameliorates the dystrophic phenotype in mdx mouse.

Authors: Miller, Gaynor  Moore, Chris J  Terry, Rebecca  La Riviere, Tracy  Mitchell, Andrew  Piggott, Robert  Dear, T Neil  Wells, Dominic J  Winder, Steve J 
Citation: Miller G, etal., Hum Mol Genet. 2012 Oct 15;21(20):4508-20. Epub 2012 Jul 18.
Pubmed: (View Article at PubMed) PMID:22810924
DOI: Full-text: DOI:10.1093/hmg/dds293

Loss of dystrophin protein due to mutations in the DMD gene causes Duchenne muscular dystrophy. Dystrophin loss also leads to the loss of the dystrophin glycoprotein complex (DGC) from the sarcolemma which contributes to the dystrophic phenotype. Tyrosine phosphorylation of dystroglycan has been identified as a possible signal to promote the proteasomal degradation of the DGC. In order to test the role of tyrosine phosphorylation of dystroglycan in the aetiology of DMD, we generated a knock-in mouse with a phenylalanine substitution at a key tyrosine phosphorylation site in dystroglycan, Y890. Dystroglycan knock-in mice (Dag1(Y890F/Y890F)) had no overt phenotype. In order to examine the consequence of blocking dystroglycan phosphorylation on the aetiology of dystrophin-deficient muscular dystrophy, the Y890F mice were crossed with mdx mice an established model of muscular dystrophy. Dag1(Y890F/Y890F)/mdx mice showed a significant improvement in several parameters of muscle pathophysiology associated with muscular dystrophy, including a reduction in centrally nucleated fibres, less Evans blue dye infiltration and lower serum creatine kinase levels. With the exception of dystrophin, other DGC components were restored to the sarcolemma including α-sarcoglycan, α-/ß-dystroglycan and sarcospan. Furthermore, Dag1(Y890F/Y890F)/mdx showed a significant resistance to muscle damage and force loss following repeated eccentric contractions when compared with mdx mice. While the Y890F substitution may prevent dystroglycan from proteasomal degradation, an increase in sarcolemmal plectin appeared to confer protection on Dag1(Y890F/Y890F)/mdx mouse muscle. This new model confirms dystroglycan phosphorylation as an important pathway in the aetiology of DMD and provides novel targets for therapeutic intervention.

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CRRD ID: 12880014
Created: 2017-05-01
Species: All species
Last Modified: 2017-05-01
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.