This potassium channel is controlled by G proteins. It plays a role in granule cell differentiation, possibly via membrane hyperpolarization. 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. May associate with GIRK1 or GIRK4 to form a G-protein-activated heteromultimer pore-forming unit. The resulting inward current is much larger. Interacts (via PDZ-binding motif) with SNX27 (via PDZ domain); the interaction is required when endocytosed to prevent degradation in lysosomes and promote recycling to the plasma membrane (By similarity). Additional isoforms seem to exist. Cerebellum, testes, cortex and substentia nigra. Defects in Kcnj6 are the cause of the weaver (wv) phenotype. Homozygous animals suffer from severe ataxia that is obvious by about the second postnatal week. The cerebellum of these animals is drastically reduced in size due to depletion of the major cell type of cerebellum, the granule cell neuron. Heterozygous animals are not ataxic but have an intermediate number of surviving granule cells. Male homozygotes are sterile, because of complete failure of sperm production. Both hetero- and homozygous animals undergo sporadic tonic-clonic seizures. Belongs to the inward rectifier-type potassium channel (TC 1.A.2.1) family. KCNJ6 subfamily.