Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by external barium. This potassium channel is controlled by G proteins. {ECO:0000269|PubMed:22315453, ECO:0000269|PubMed:22628607, ECO:0000269|PubMed:24037882, ECO:0000269|PubMed:27099398, ECO:0000269|PubMed:27293068, ECO:0000269|PubMed:8558261, ECO:0000269|PubMed:8868049}. This is the function of ENSG00000120457 (KCNJ5, potassium inwardly rectifying channel subfamily J member 5).