G-protein gated inwardly rectifying K-channel 1

Alternate Nomenclature: NP_113798, Inward rectifier K(+) channel Kir3.1

G protein-gated inwardly rectifying potassium (GIRK) channels hyperpolarize neurons in response to activation of many G-protein coupled receptors and control the excitability of neurons at post synaptic terminals through GIRK-mediated self-inhibition, slow synaptic potentials and volume transmission. GIRK channels composed of a4 subunits (GIRK1-4), the native GIRK channels are heteromers composed of GIRK1 and either GIRK2, GIRK3, or GIRK4.   The channel functioning and trafficking are highly dependent on their subunit composition. GIRK activity has an important role in physiological responses, including pain perception and memory modulation. Abnormal GIRK function has been implicated in altering neuronal excitability and cell death that may be important in the pathophysiology of human diseases such as epilepsy, Down’s syndrome, Parkinson’s disease and drug addiction.(1). GIRK channels are expressed in the brain, heart, skeletal muscle, and endocrine tissue. GIRK channels are members of the super-family of proteins known as inward rectifier K+ (Kir) channels that function to stabilize the cell resting membrane potential near the K+ equilibrium potential (EK). These channels generate slow inhibitory postsynaptic potentials following the activation of Gi/o-protein-coupled receptors .The major role of the GIRK channels is to mediate inhibitory responses in the nervous system by decreasing neuronal excitability. GIRK channels also play role at presynaptic sites due to their localization in axon terminals. A major G protein-coupled receptor activating postsynaptic GIRK channels is the metabotropic γ-aminobutyric acid (_B) (GABA_B) receptor. GIRK channel-mediated inhibition of glutamate release occurs through GABA_B receptors in the cerebral cortex.

Four different cDNAs encode GIRK channel subunits in mammals (GIRK1–4) and they combine to form functional homomeric as well as heteromeric channels. In central neurons most neuronal GIRK channels are heteromeric complexes containing both GIRK1 and GIRK2 (2). GIRK1, GIRK2, and GIRK3 subunits are expressed in a number of regions of the brain including the hippocampus, cerebellum, substantia nigra, locus coeruleus, and ventral tegmental area. Cerebellar Purkinge cells aso express a high density of GABA_B receptors, which are mainly localized at postsynaptic sites, but a small fraction is found presynaptically at parallel fiber terminals. GIRK1 and GIRK2 subunits are expressed in the superficial layers of the spinal dorsal horn and are enriched in the postsynaptic membranes of substantia gelatinosa neurons (3).  In neuronal tissue GIRK subunits combine to form both heterotetrameric (e.g., GIRK1/GIRK2, GIRK1/GIRK3, etc.) and homotetrameric (GIRK1/GIRK2) channels. In the atrial myocardium and sinus and atrioventricular nodes of the heart, GIRK channels are composed of heteromers of GIRK1 and GIRK4 subunits (4). 

The GIRK1-selective antibodies were generated using a peptide selected form a region between amino acids 360-420.  The GIRK1 antibodies are affinity purified over immobilized antigen based affinity chromatography, and the purified immunoglobulins are stabilized in antibody stabilization buffer for long-term storage.  FabGennix Int. Inc. will provide limited quantities of antigenic blocking peptides for competition assays involving GIRK1antibody. Antibodies to GIRK1 label ~61kDa protein in Western blot positive control and several other tissues.  FabGennix Inc. will conjugate this and other antibodies from its catalog to either secondary enzymes (alk-Pase or HRP) or fluorescent probes at a nominal cost upon request.  FabGennix also provides custom antibody production services for researchers that are looking for high affinity mono and polylconal antibodies in various species. We specialize in making application specific antibodies that are useful in IHC, confocal and other applications where native antigen is detected. For a complete listing of all FabGennix antibodies please visit www.Fabgennix.com.

For research use only, not for diagnostic or therapeutic use.