Oligodendrocyte transmembrane protein: a novel member of the glutamate-binding protein subfamily.
Oligodendrocytes (OLGs) are cells from the central nervous system that synthesize, assemble, and maintain myelin, the multilamellar membrane that surrounds axons and facilitates the fast conduction of nerve impulses. We have shown that OLGs initiate their myelinogenic phenotype upon adhesion to GRASP, a heparin-binding glycoprotein that we purified from horse serum. In an attempt to identify the genes implicated in establishing this phenotype, we isolated a novel 3500 bp cDNA related to, but distinct from, a subfamily of glutamate-binding proteins (GBP). The cDNA encodes a protein of 511 amino acids, whose predicted sequence can be modeled as a tetrahelical integral protein with a large external loop and with the N- and C-termini located inside the cell. We have named this protein oligodendrocyte transmembrane protein (OTMP). Transcription of the message is induced upon OLG acquiring a myelinogenic phenotype (i.e., upon adhesion). The temporal expression in conjunction with the structural and biochemical features of OTMP is suggestive of a signaling receptor with a role in myelinogenesis.
Szuchet
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Department of Neurology and Brain Research Institute, University of Chicago, Chicago, Illinois 60637, USA. szuchet@neurology.uchicago.edu
Plachetzki
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Eaton
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005971:Glutamates / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009185:Myelin Proteins / Q000096:biosynthesis; D009836:Oligodendroglia / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012756:Sheep
D002352:Carrier Proteins; D018076:DNA, Complementary; D005971:Glutamates; D008565:Membrane Proteins; D009185:Myelin Proteins; C428344:OTMP protein, Ovis aries; D012333:RNA, Messenger