Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Ionotropic glutamate receptors mediate fast excitatory neurotransmission in the mammalian receptors according to their different pharmacology and sequences (1,2). A wealth of experimental data indicates that the NMDA and AMPA subtypes of glutamate receptors unlike the Glycine, GABA and Nicotinic Acetylcholine receptors (3) which have four transmembrane domains, have only three transmembrane domains and one cytoplasmic re-entry loop (4-8). Because of the distinct channel forming properties of kainate receptors (9-10) the topology of AMPA and NMDA receptors cannot be extrapolated to the kainate receptors. The current evidence for the transmembrane topology of kainate receptors is derived from mapping of the three C-terminal N-glycosylation sites, immunostaining with a C-terminal antibody of the GluR6 subunit (11) and a biochemical analysis of a distantly related fish kainate binding protein (12). Despite these studies the precise location of the first transmembrane domain of the kainate receptor subunits has not been established. We employed a PCR based mutagenesis approach to obtain a number of truncated N-terminal domains of the rat kainate receptor subunit KA-1 incorporating different N- and C-terminal epitope tags. The pattern of cell surface expression of the truncated constructs and identification of the position of the tagged termini in relation to the cell membrane and cell cytoplasm have allowed us to define the first transmembrane domain of the kainate receptor.

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Poster Number PAsoloviev0441
Keywords: kainate receptor, transmembrane, topology, ampa receptor, nmda receptor