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Limb-girdle muscular dystrophy type 2H (LGMD2H) and sarcotubular myopathy are hereditary skeletal muscle disorders caused by mutations in TRIM32. We previously identified TRIM32 as an E3 ubiquitin ligase that binds to myosin and ubiquitinates actin. To date four TRIM32 mutations have been linked to LGMD2H, all of which occur in the C-terminal NHL domains.(More)
Dystrophin-deficient muscles experience large reductions in expression of nitric oxide synthase (NOS), which suggests that NO deficiency may influence the dystrophic pathology. Because NO can function as an antiinflammatory and cytoprotective molecule, we propose that the loss of NOS from dystrophic muscle exacerbates muscle inflammation and fiber damage by(More)
The cysteine protease calpain 3 (CAPN3) is essential for normal muscle function, since mutations in CAPN3 cause limb girdle muscular dystrophy type 2A. Previously, we showed that myoblasts isolated from CAPN3 knockout (C3KO) mice were able to fuse to myotubes; however, sarcomere formation was disrupted. In this study we further characterized morphological(More)
Human tibial muscular dystrophy and limb-girdle muscular dystrophy 2J are caused by mutations in the giant sarcomeric protein titin (TTN) adjacent to a binding site for the muscle-specific protease calpain 3 (CAPN3). Muscular dystrophy with myositis (mdm) is a recessive mouse mutation with severe and progressive muscular degeneration caused by a deletion in(More)
Reduced sarcolemmal integrity in dystrophin-deficient muscles of mdx mice and Duchenne muscular dystrophy (DMD) patients has been reported to result in altered calcium homeostasis. Previous studies have shown a correlative relationship between calcium-dependent protease (calpain) activity in dystrophic muscle and muscle necrosis, but have not tested whether(More)
Mutations in the non-lysosomal cysteine protease calpain 3 cause limb-girdle muscular dystrophy type 2A (LGMD2A). Our previous studies of the calpain 3 knockout mouse (C3KO) suggested a role for calpain 3 in sarcomere formation and remodeling. Calpain 3 may mediate remodeling by cleavage and release of myofibrillar proteins, targeting them for(More)
The hypothesis that changes in muscle activation and loading regulate the expression and activity of neuronal nitric oxide (NO) synthase (nNOS) was tested using in vitro and in vivo approaches. Removal of weight bearing from rat hindlimb muscles for 10 days resulted in a significant decrease in nNOS protein and mRNA concentration in soleus muscles, which(More)
Mutations in the non-lysosomal cysteine protease calpain-3 cause autosomal recessive limb girdle muscular dystrophy. Pathological mechanisms occurring in this disease have not yet been elucidated. Here, we report both morphological and biochemical evidence of mitochondrial abnormalities in calpain-3 knockout (C3KO) muscles, including irregular(More)
Many features of dystrophin-deficient muscle pathology are not clearly related to the loss of mechanical support of the muscle membrane by dystrophin. In the present review, evidence that supports a role for the immune system in promoting the pathology of dystrophinopathy is presented. The findings summarized here indicate that specific, cellular immune(More)
Limb girdle muscular dystrophy 2H is caused by mutations in the gene encoding the E3 ubiquitin ligase, TRIM32. Previously, we generated and characterized a Trim32 knockout mouse (T32KO) that displays both neurogenic and myopathic features. The myopathy in these mice is attributable to impaired muscle growth, associated with satellite cell senescence and(More)