title: Reconstitution of invertebrate glutamate receptor function depends on stargazin-like proteins.
abstract: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPARs) are a major subtype of ionotropic glutamate receptors (iGluRs) that mediate rapid excitatory synaptic transmission in the vertebrate brain. Putative AMPARs are also expressed in the nervous system of invertebrates. In Caenorhabditis elegans, the GLR-1 receptor subunit is expressed in neural circuits that mediate avoidance behaviors and is required for glutamate-gated current in the AVA and AVD interneurons. Glutamate-gated currents can be recorded from heterologous cells that express vertebrate AMPARs; however, when C. elegans GLR-1 is expressed in heterologous cells, little or no glutamate-gated current is detected. This finding suggests that other receptor subunits or auxiliary proteins are required for function. Here, we identify Ce STG-1, a C. elegans stargazin-like protein, and show that expression of Ce STG-1 together with GLR-1 and the CUB-domain protein SOL-1 reconstitutes glutamate-gated currents in Xenopus oocytes. Ce STG-1 and homologues cloned from Drosophila (Dro STG1) and Apis mellifera (Apis STG1) have evolutionarily conserved functions and can partially substitute for one another to reconstitute glutamate-gated currents from rat, Drosophila, and C. elegans. Furthermore, we show that Ce STG-1 and Apis STG1 are primarily required for function independent of possible roles in promoting the surface expression of invertebrate AMPARs.
authors.affiliation: Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA.
authors.forename: Craig S
authors.initials: CS
authors.lastname: Walker
authors.forename: Penelope J
authors.initials: PJ
authors.lastname: Brockie
authors.forename: David M
authors.initials: DM
authors.lastname: Madsen
authors.forename: Michael M
authors.initials: MM
authors.lastname: Francis
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.forename: Sri
authors.initials: S
authors.lastname: Koduri
authors.forename: Jerry E
authors.initials: JE
authors.lastname: Mellem
authors.forename: Nathalie
authors.initials: N
authors.lastname: Strutz-Seebohm
authors.forename: Andres V
authors.initials: AV
authors.lastname: Maricq
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000235:genetics / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015220:Calcium Channels / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D018091:Receptors, AMPA / Q000502:physiology*; D014981:Xenopus
chemical_list: D029742:Caenorhabditis elegans Proteins; D015220:Calcium Channels; D019476:Insect Proteins; D018091:Receptors, AMPA; C481340:SOL-1 protein, C elegans; C512985:STG-1 protein, C elegans; C096470:glr-1 protein, C elegans