An inward rectifier potassium channel complex expressed in cardiac muscle, specifically the sinoatrial node and atria, where it controls the heart rate, via regulation by G protein-coupled receptor signalling. In mammals it is composed of GIRK1 (or Kir3.1) and GIRK4 (or Kir3.4) subunits.
Source:PMID:9765280,
GOC:ame
Comment
Examples of this are KCNJ3 and KCNJ5 in human (Uniprot symbols P48549 and P48544) in PMID:9765280 inferred from orthology sequence evidence.