CHARACTERIZATION OF DYSTROGLYCAN - LAMININ INTERACTION IN PERIPHERAL-NERVE

Dystroglycan is encoded by a single gene and cleaved into two proteins , alpha- and beta-dystroglycan, by posttranslational processing. The 1 20-kDa peripheral nerve isoform of alpha-dystroglycan binds laminin-2 comprised of the alpha 2, beta 1, and gamma 1 chains. In congenital mu scular dystrophy and dy mice deficient in laminin alpha 2 chain, perip heral myelination is disturbed, suggesting a role for the dystroglycan -laminin interaction in peripheral myelinogenesis. To begin to test th is hypothesis, we have characterized the dystroglycan-laminin interact ion in peripheral nerve, We demonstrate that (1) alpha-dystroglycan is an extracellular peripheral membrane glycoprotein that links beta-dys troglycan in the Schwann cell outer membrane with laminin-2 in the end oneurial basal lamina, and (2) dystrophin homologues Dp116 and utrophi n are cytoskeletal proteins of the Schwann cell cytoplasm, We also pre sent data that suggest a role for glycosylation of alpha-dystroglycan in the interaction with laminin.