title: Electron microscopic evidence for a mucin-like region in chick muscle alpha-dystroglycan.
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.
authors.affiliation: Department of Biophysical Chemistry, Biozentrum, University of Basel, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Brancaccio
authors.forename: T
authors.initials: T
authors.lastname: Schulthess
authors.forename: M
authors.initials: M
authors.lastname: Gesemann
authors.forename: J
authors.initials: J
authors.lastname: Engel
mesh_terms: D000818:Animals; D002645:Chickens; D003598:Cytoskeletal Proteins / Q000302:isolation & purification / Q000648:ultrastructure*; D049030:Dystroglycans; D007797:Laminin / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009077:Mucins / Q000648:ultrastructure; D009206:Myocardium / Q000737:chemistry*; D011485:Protein Binding
chemical_list: D003598:Cytoskeletal Proteins; D007797:Laminin; D008562:Membrane Glycoproteins; D009077:Mucins; D049030:Dystroglycans