Membrane changes in Duchenne/Becker muscular dystrophy: lectin binding and localization of dystrophin
Voit, T.; Patel, K.; Sewry, C.A.; Strong, P.N.; Dubowitz, V.; Dunn, M.J.
Monatsschrift Kinderheilkunde Organ der Deutschen Gesellschaft für Kinderheilkunde 137(1): 20-27
1989
ISSN/ISBN: 0026-9298 PMID: 2646527 Document Number: 335162
An RCA I-lectin binding glycoprotein of Mr = 370 kD is missing from or altered in the plasma membrane of Duchenne muscular dystrophy (DMD) skeletal muscle. In the present study the carbohydrate chain of this glycoprotein was localized to the external face of the plasma membrane in human skeletal muscle, and dystrophin, the protein product of the DMD gene, was localized to the inner (cytoplasmic) face. On double labelled Western blots the two proteins appeared as closely apposed but distinctly separate bands. Comparison of the plasma membrane binding of five lectins with overlapping sugar specificities in skeletal muscle from patients with DMD and the allelic milder disease form, Becker muscular dystrophy (BMD) showed that the RCA I-binding glycoprotein also strongly binds to phytohaemagglutinin, thereby largely characterising the carbohydrate binding site. This glycoprotein was absent or altered in DMD and markedly reduced in clinically manifest BMD but present in preclinical clinical BMD. There was no general depletion of plasma membrane glycoproteins in DMD because consistent plasma membrane binding could be demonstrated by peanut and maclura pomifera lectin. The possible implications of these findings for the pathogenesis of DMD/BMD are discussed.