A protein that has channel activity. Channel proteins enable energy-independent facilitated diffusion, mediated by passage of a solute through a transmembrane aqueous pore or channel. [ PRO:XQ http://amigo.geneontology.org/amigo/term/GO:0015267 ]
Synonyms: pore class transporter protein channel/pore class transporter protein pore protein nonselective channel protein fam:chan channel-forming toxin protein