Expression and localization of the neuronal glycine receptor beta-subunit in human, rabbit and rat kidneys

The glycine receptor (GlyR) is a ligand-gated Cl- channel composed of two transmembrane subunits, alpha and beta, and gephyrin. The goal of this study was to determine whether the alpha- and/or beta-subunits of the GlyR are expressed in human, rabbit and/or rat kidneys. Screening of human and rat kidney cortex cDNA libraries identified polymerase chain reaction products that were identical to the neuronal GlyR beta-subunit. Sequencing revealed that rat kidney cortex and neuronal GlyR beta-subunits were identical. RNA isolated from the S2 segment of rabbit renal proximal tubules (RPT) and rat and rabbit kidney cortex was amplified following reverse transcription and gave similar results to that of human and rat kidney cDNA libraries. Degenerate primers against all GlyR alpha-subunits did not yield a product from rat and rabbit kidney cortex RNA, or from human and rat kidney cortex cDNA libraries. Immunofluorescence studies localized the beta-subunit and gephyrin to the basolateral membrane of rabbit RPT. These results provide compelling evidence for the GlyR beta-subunit, but not the alpha-subunit, in human, rabbit and rat kidney cortex.