The subcellular distribution of chromosome 6-encoded dystrophin-related protein in the brain.

Chromosome 6-encoded dystrophin-related-protein (DRP) shows significant structural similarities to dystrophin at the carboxyl terminus, though the two proteins are encoded on different chromosomes. Both DRP and dystrophin are expressed in muscle and brain and show some similarity in their subcellular localization. For example, in skeletal muscle both are expressed at neuromuscular and myotendinous junctions. However, while dystrophin is absent or severely reduced in Duchenne/Becker muscular dystrophy, DRP continues to be expressed. Within the brain, dystrophin is enriched at the postsynaptic regions of specific subsets of neurons, while the distribution of DRP is yet to be described. In this study we demonstrate a distinct though highly specific pattern of distribution of DRP in the brain. DRP is enriched in the choroid plexus, pia mater, intracerebral vasculature, and ependymal lining. Within the parenchyma proper, DRP is located at the inner plasma face of astrocytic foot processes at the abluminal aspect of the blood-brain barrier. The distribution of DRP is conserved across a large evolutionary distance, from mammals to elasmobranchs, suggesting that DRP may play a role in the maintenance of regional specializations in the brain.