Electron microscopic evidence for a mucin-like region in chick muscle alpha-dystroglycan

FEBS Lett. 1995 Jul 10;368(1):139-42. doi: 10.1016/0014-5793(95)00628-m.

Abstract

alpha-Dystroglycan has been isolated from chicken cardiac muscle and its molecular weight was estimated to be approximately 135 kDa. The avian protein interacts with murine Engelbreth-Holm-Swarm (EHS) tumor laminin via interaction with the C-terminal LG4 and LG5 domains (fragment E3) of the laminin alpha-chain. This laminin binding is calcium-dependent and can be competed by heparin. Electron microscopy investigation on the shape of alpha-dystroglycan suggests that the core protein consists of two roughly globular domains connected by a segment which most likely corresponds to a mucin-like central region also predicted by sequence analysis on mammalian isoforms. This segment may act as a spacer in the dystrophin-associated glycoproteins complex exposing the N-terminal domain of alpha-dystroglycan to laminin in the extracellular space.

MeSH terms

  • Animals
  • Chickens
  • Cytoskeletal Proteins / isolation & purification
  • Cytoskeletal Proteins / ultrastructure*
  • Dystroglycans
  • Laminin / metabolism
  • Membrane Glycoproteins / isolation & purification
  • Membrane Glycoproteins / ultrastructure*
  • Microscopy, Electron
  • Mucins / ultrastructure
  • Myocardium / chemistry*
  • Protein Binding

Substances

  • Cytoskeletal Proteins
  • Laminin
  • Membrane Glycoproteins
  • Mucins
  • Dystroglycans