Background：

Potassium channels are present in most mammalian cells， where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein， which has a greater tendency to allow potassium to flow into a cell rather than out of a cell， is controlled by G-proteins and plays an important role in regulating heartbeat. It associates with three other G-protein-activated potassium channels to form a heteromultimeric pore-forming complex that also couples to neurotransmitter receptors in the brain and whereby channel activation can inhibit action potential firing by hyperpolarizing the plasma membrane. These multimeric G-protein-gated inwardly-rectifying potassium (GIRK) channels may play a role in the pathophysiology of epilepsy， addiction， Down’s syndrome， ataxia， and Parkinson’s disease. Alternative splicing results in multiple transcript variants encoding distinct proteins.