Transmembrane topology of two kainate receptor subunits revealed by N-glycosylation.
Glutamate receptors are the primary excitatory neurotransmitter receptors in vertebrate brain and are of critical importance to a wide variety of neurological processes. Recent reports suggest that ionotropic glutamate receptors may have a unique transmembrane topology not shared by other ligand-gated ion channels. We report here the cloning of cDNAs from goldfish brain encoding two homologous kainate receptors with protein molecular masses of 41 kDa. Using a cell-free translation/translocation system, we show that (i) a portion of these receptors previously thought to be a large intracellular loop is actually located extracellularly and (ii) the putative second transmembrane region of the receptor thought to line the ion channel may not be a true membrane-spanning domain. An alternative model for the transmembrane topology of kainate receptors is proposed that could potentially serve as a framework for future detailed study of the structure of this important class of neurotransmitter receptors.
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Department of Pharmacology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.
Oswald
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry; D002474:Cell-Free System; D003001:Cloning, Molecular; D004247:DNA; D006031:Glycosylation; D006054:Goldfish; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D011487:Protein Conformation; D018092:Kainic Acid Receptors / Q000737:chemistry* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D004247:DNA; D018092:Kainic Acid Receptors