ion channel activity cation channel activity GO:0015338 GO:0005261 Reactome:R-HSA-4420052 Reactome:R-HSA-2089943 non-selective cation channel activity molecular_function cation diffusion facilitator activity Reactome:R-HSA-1168376 GO:0015281 Reactome:R-HSA-426223 Enables the energy-independent passage of cations across a lipid bilayer down a concentration gradient. Reactome:R-HSA-169683 Reactome:R-HSA-1296043 inorganic cation transmembrane transporter activity