Gamma-aminobutyric acid receptor subunit beta-3 homopentamer (GABRB3 homopentamer)

The Gamma-aminobutyric acid receptor subunit beta-3 (GABRB3) homopentamer is a homomeric ligand-gated ion channel composed of five identical beta-3 subunits. While most native GABAA receptors are heteromeric complexes typically containing alpha, beta, and gamma subunits, the beta-3 subunit is unique in its ability to form functional homopentameric channels that can reach the cell surface. These homopentamers are characteristically insensitive to the neurotransmitter GABA but can be directly activated by other physiological and pharmacological ligands, such as protons, histamine, and general anesthetics like propofol and etomidate. This distinct pharmacological profile makes the beta-3 homopentamer a significant model for structural biology and a potential target for therapeutic intervention in conditions involving pH changes, such as ischemia. The GABRB3 subunit plays a vital role in the development and maintenance of inhibitory signaling within the central nervous system. Genetic variations, including mutations and deletions in the 15q11-q13 chromosomal region where the GABRB3 gene is located, are strongly linked to neurodevelopmental disorders such as Angelman syndrome, autism spectrum disorder, and epilepsy. Drugs that interact with this receptor typically function as positive allosteric modulators or direct agonists, enhancing chloride conductance to reduce neuronal excitability.

Other names

GABRB3 homomerHomomeric beta-3 GABAA receptorGABRB3 pentamerBeta-3 homopentameric GABAA receptorGABAA receptor beta-3 homopentamerGABAA receptor beta3-containing homopentamer

Direct activation of the chloride channel by protons or anesthetics, and positive allosteric modulation of the channel's open probability.