Coordinate enrichment of cranin (dystroglycan) subunits in synaptic membranes of sheep brain

Cranin (dystroglycan), a mucin-like extracellular matrix receptor comprised of two subunits (alpha and beta), is involved in regulating cell-matrix interactions in a variety of tissues, including brain. A basic issue remains unresolved concerning the distribution of cranin in brain: are the alpha and beta subunits coordinately expressed at the synapse? We report here that cranin is indeed enriched progressively in synaptosomes and synaptic membranes of sheep brain, as assessed by immunoblotting and laminin-blotting assays, and that the extent of enrichment is similar for both alpha and beta subunits. These findings support the hypothesis that cranin (dystroglycan) contributes to synaptic function in the CNS.