Distribution and Localization of the GABAB Receptor

The functional GABAB receptors (GABABRs) are formed by obligate heteromers composed of two principal subunits named GABAB1 and GABAB2. In Drosophila melanogaster three GABAB subunits have been identified: GB1, GB2, and GB3. The GB1 and GB2 subunits need to be coexpressed in Xenopus oocytes or in mammalian cell lines to produce functional GABABRs. A subfamily of potassium channel tetramerization domain-containing (KCTD8, 12, 12b, and 16) proteins that are constituents of native GABABRs were recently identified. KCTDs show a temporal and spatial distribution pattern that may contribute to the heterogeneity of native GABABRs and their pharmacological properties.