Dystrophin: Localization and presumed function

Abstract

To determine the localization and functional significance of dystrophin, we studied various tissues from almost the entire body of control and mdx mice, and control rats, using polyclonal antibodies against dystrophin. We observed a dystrophin reaction in synaptic regions such as neuromuscular junctions, the equatorial region of intrafusal muscle fibers, the outer plexiform layer of the retina, the myoepithelial cell layer of salivary and sweat glands, tactile nerve endings, and neurons in the brain. These dystrophin-positive regions reportedly contain actin filaments as a common characteristic, which is compatible with the dystrophin cDNA sequence. Dystrophin was absent in these regions in mdx mice. These results suggest that dystrophin plays an important physiological and/or structural role in cell motility as a trigger for propagating contractile force in, for example, the conduction system, with some relationship between actin filaments.

Differences in both inositol 1,4,5-trisphosphate mass and inositol 1,4,5-trisphosphate receptors between normal and dystrophic skeletal muscle cell lines

“…A feedback mechanism that would imply downregulation of receptors upon increased levels of ligand (free IP 3 ) is apparently absent in dystrophic cells and could be the cause of altered calcium levels. Regulation of intracellular calcium has been reported to be altered in dystrophic muscle cells both in vivo 23 and in vitro 28 ; if diseased cells have a defec- Confluent plates of XLT 4-2 cells (3-5 days), were rinsed with PBS, harvested with a rubber policeman, and homogenized with Dounce. The homogenate was centrifuged at 1000 g for 10 min (nuclear fractions), and the supernate was centrifuged at 5000 g for 10 min.…”

“…15 This deficiency results in the absence of a function associated with the protein at the cell membrane level, with subsequent thin filament-membrane impairments, increased intracellular Ca 2+ concentrations, and elevated protein degradation. 28,32 Our goal in this work was to investigate whether elements important in IP 3 -mediated processes, such as the total mass of IP 3 and the level of IP 3 receptors, are altered in dystrophin-deficient muscle cells.…”

Ion channels in a skeletal muscle cell line from a Duchenne muscular dystrophy patient

“…Differentiation media consisted of F,,/D enriched with 1% bovine serum and 1% stock supplement as described by Orozco et a1. 26 A complete description of all culture procedures mentioned herein have been reported in detail. 5 For 3H-PN200-1 10 binding studies, cells were cultured for 1 week before the experiment in 15-cm-diameter culture dishes.…”

Duchenne Muscular Dystrophy and Brain Function

“…Dp 116 has been localised to adult peripheral nerves, along the Schwann cell membrane and fibroblasts Labarque et al 2008). Dp71 is expressed in a variety of tissues, predominately the CNS (where it is the most abundant dystrophin gene product), it has multiple isoforms each with specific subcellular localisations (Austin et al 1995(Austin et al , 2000Bar et al 1990;Blake & Kroger 2000;Ceccarini et al 2002;Chamberlain et al 1988;Greenberg et al 1996;Holder et al 1996;Huard et al 1992;Ilarraza-Lomeli et al 2007;Lederfein et al 1992;Miyatake et al 1991;Rapaport et al 1992). Dp71 has been localised to hippocampus (CA1 and dentate gyrus), olfactory bulb as well as perivascular astrocyte feet (Daoud et al 2009).…”