Abstract
Glycine is a major inhibitory neurotransmitter in central or peripheral nervous system, and the response is mediated by several glycine receptors (GlyRs) . Here, we report cloning and analysis of a novel variant of GlyRα1 subunit. The variant, designated as GlyRα1del, involves truncated cytoplasmic region between transmenbrane domain (TM)3 and TM4, and the truncation is contributed by an alternative start site of exon 9. Flag-tagged GlyRα1del, transfected and overexpressed in COS-7 cells, revealed an about 44 kDa immunoreactive band by immunoblotting. Immunofluorescence analysis showed that it seemed to localize at cell surface as similarly as GlyRα1. We further transfected HEK293 cells with GlyRα1 or GlyRα1del, and currents activated by glycine were examined using the whole-cell patch-clamp recording technique. Maximal currents (holding potential at -45 mV) and I-V curves for GlyRα1del showed no clear difference from that for GlyRα1. We also examined the property on the glycine dose-response curve. In the cells with GlyRα1del, EC50 and Hill coefficient for the glycine current were 71.5 ± 3.4 μM (mean ± SEM) and 2.8 ± 0.1, respectively. By contrast, those with GlyRα1 were 43.3 ± 7.5 μM and 2.7 ± 0.2, respectively. Further experiments are in progress to evaluate the functional characterization of GlyRα1del. [Jpn J Physiol 54 Suppl:S138 (2004)]
