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Investigation of Myelin/Oligodendrocyte Glycoprotein Membrane Topology
Author(s) -
Kroepfl John F.,
Viise Laura R.,
Charron Audra J.,
Linington Chris,
Gardinier Minnetta V.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.67052219.x
Subject(s) - myelin oligodendrocyte glycoprotein , oligodendrocyte , glycoprotein , myelin , membrane glycoproteins , myelin sheath , topology (electrical circuits) , membrane topology , myelin associated glycoprotein , chemistry , microbiology and biotechnology , neuroscience , membrane , membrane protein , biology , biochemistry , mathematics , central nervous system , combinatorics
Myelin/oligodendrocyte glycoprotein (MOG) is a CNS‐specific integral membrane protein that is an atypical member of the immunoglobulin (Ig) superfamily with two potential transmembrane domains based upon hydropathy analysis. With only one other exception, all Ig family members possess a single or no membrane spanning region. In order to analyze MOG membrane topology, we prepared stably transfected cells that express mouse MOG and used three domain‐specific antisera to ascertain the localization of these hydrophilic domains. As expected, MOG's glycosylated N‐terminal Ig‐like domain was identified as extracellular, because membrane permeabilization was not required for immunoreactivity with the MOG 1–125 antiserum. In contrast, both MOG 154–169 and MOG 198–218 antisera stained cells only upon permeabilization. These data indicate that only MOG's N‐terminal hydrophobic domain spans the lipid bilayer, and we propose that MOG's C‐terminal hydrophobic domain associates with the cytoplasmic face of the plasma membrane. As for MOG's second hydrophobic domain, it is clear that either orientation (transmembrane versus membrane‐associated) would be unique among Ig‐like proteins, and the implications of our proposed topology for MOG in oligodendroglial plasma membrane are discussed.