Gamma-aminobutyric acid type A receptor subunit pi (GABRP)

Gamma-aminobutyric acid type A receptor subunit pi (GABRP) is a protein subunit encoded by the GABRP gene. It is part of the GABA(A) receptor, a ligand-gated chloride ion channel mediating fast inhibitory neurotransmission in the central nervous system. The pi subunit is structurally related to other GABA(A) receptor subunits, but exhibits distinctive tissue distribution and pharmacological features. GABRP is expressed not only in the brain but also in several non-neuronal tissues such as the uterus, placenta, pancreas, gastrointestinal tract, lung, kidney, immune cells, and mammary gland. GABRP does not form homomeric receptors but co-assembles with other GABA(A) receptor subunits, generating receptors with unique pharmacological properties, such as insensitivity to benzodiazepines and high sensitivity to zinc and neurosteroids. Functionally, GABRP-containing receptors play roles in inhibitory neurotransmission, regulation of uterine contractility, and may be implicated in the proliferation and progression of certain cancers. Altered expression or function of GABRP-containing receptors is associated with various diseases, including cancers and neuropsychiatric disorders.

Other names

Gamma-aminobutyric acid receptor subunit piGABA(A) receptor subunit piGABAAR subunit piGABA(A) receptor, pigamma-aminobutyric acid (GABA) A receptor, piGABA(A) receptor pi subunit

Channel opening via GABA binding, increasing chloride conductance, leading to neuronal hyperpolarization and inhibition. Differential sensitivity to neurosteroids (e.g., pregnanolone, allopregnanolone). Inhibition by zinc ions. Mechanism and pharmacology may differ for π subunit-containing receptors versus other GABA(A) receptor isoforms. No strong evidence of benzodiazepine activity at GABRP subunit-containing receptors; GABAARs are overall targets of many drugs, but the pi subunit specifically does not respond to classic benzodiazepines.