GABAA Receptor Alpha 1 Beta 3 Gamma 2

Family:
GABA Receptors (Cys-loop ligand-gated ion channels)

Subgroups:
The GABA receptor family has further been divided into GABA_A, GABA_B and GABA_A-ρ (also called GABA_C) receptors.

Topology:
As typical for Cys-loop receptors, generally four transmembrane spanning domains TM1-TM4 form one receptor subunit, five or four subunits form a pore, several heteromeric combinations are known.
GABA_A: Oligomerization of typically five subunits, heteromeric combinations are known of α subunits (GABRA1 - GABRA6), β subunits (GABRB1 - GABRB3) and γ subunits (GABRG1 - GABRG3), as well as δ (GABRD), an ε (GABRE), a π (GABRP), and a θ (GABRQ). The most common type is (α1)₂(β2)₂(γ2), minimal requirement is  the inclusion of α and β subunits.
GABA_B: Heterodimer (GABBR1, GABBR2)
GABA_A-ρ: Oligomerization of five subunits, heteromeric combinations of three GABA_A-ρ subunits are known (GABRR1, GABRR2, GABRR3)

Regulation and Function:
GABA_A and GABA_A-ρ receptors are ligand-gated ion channels (ionotropic receptors); whereas GABA_B receptors are G protein-coupled receptors (metabotropic receptors). All respond to the neurotransmitter gamma-aminobutyric acid (GABA), the main inhibitory transmitter in the mammalian CNS.