Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. There are two major classes of GABA receptors: the GABAA and the GABAB subtype of receptors. GABAB receptors are heterodimeric G protein-coupled receptors that mediate slow synaptic inhibition in the central nervous system. Phosphorylation enhances GABAB receptor effector coupling (Couve et al., 2004). Phosphorylation of Ser923 is thought to be important in the regulation of GABAB receptor function.
