Transmembrane transporter; part of the gene cluster that mediates the biosynthesis of swainsonine, a cytotoxic fungal alkaloid and a potential cancer therapy drug (PubMed:28381497). Does not mediate the secretion of SW and the exact role of swnT in SW biosynthesis remains to be determined (By similarity). Belongs to the amino acid-polyamine-organocation (APC) superfamily. Amino acid/choline transporter (ACT) (TC 2.A.3.4) family.