Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: HUMANGGP:016487 (MTM1)
 180 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Muscle contraction relies on a highly organized intracellular network of membrane organelles and cytoskeleton proteins. Among the latter are the intermediate filaments (IFs), a large family of proteins mutated in more than 30 human diseases. For example, mutations in the DES gene, which encodes the IF desmin, lead to desmin-related myopathy and cardiomyopathy. Here, we demonstrate that myotubularin (MTM1), which is mutated in individuals with X-linked centronuclear myopathy (XLCNM; also known as myotubular myopathy), is a desmin-binding protein and provide evidence for direct regulation of desmin by MTM1 in vitro and in vivo. XLCNM-causing mutations in MTM1 disrupted the MTM1-desmin complex, resulting in abnormal IF assembly and architecture in muscle cells and both mouse and human skeletal muscles. Adeno-associated virus-mediated ectopic expression of WT MTM1 in Mtm1-KO muscle reestablished normal desmin expression and localization. In addition, decreased MTM1 expression and XLCNM-causing mutations induced abnormal mitochondrial positioning, shape, dynamics, and function. We therefore conclude that MTM1 is a major regulator of both the desmin cytoskeleton and mitochondria homeostasis, specifically in skeletal muscle. Defects in IF stabilization and mitochondrial dynamics appear as common physiopathological features of centronuclear myopathies and desmin-related myopathies.
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PMID:Myotubularin controls desmin intermediate filament architecture and mitochondrial dynamics in human and mouse skeletal muscle. 2113 8

Although myopathies and neuromuscular junction disorders are typically distinct, their coexistence has been reported in several inherited and acquired conditions. Affected individuals have variable clinical phenotypes but typically display both a decrement on repetitive nerve stimulation and myopathic findings on muscle biopsy. Inherited causes include myopathies related to mutations in BIN1, DES, DNM2, GMPPB, MTM1, or PLEC and congenital myasthenic syndromes due to mutations in ALG2, ALG14, COL13A1, DOK7, DPAGT1, or GFPT1. Additionally, a decrement due to muscle fiber inexcitability is observed in certain myotonic disorders. The identification of a defect of neuromuscular transmission in an inherited myopathy may assist in establishing a molecular diagnosis and in selecting patients who would benefit from pharmacological correction of this defect. Acquired cases meanwhile stem from the co-occurrence of myasthenia gravis or Lambert-Eaton myasthenic syndrome with an immune-mediated myopathy, which may be due to paraneoplastic disorders or exposure to immune checkpoint inhibitors.
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PMID:Trouble at the junction: When myopathy and myasthenia overlap. 3144 69