Polyamine transport systems in mammalian cells and tissues.

Polyamine transport plays an important role in the homeostatic regulation of the polyamine levels. In animals, dietary polyamines are absorbed efficiently in the intestinal tract. In the colon, luminal bacterial derived polyamines are important contributors to cellular polyamine contents. Polyamine transport involves unique uptake and export mechanisms. The amino acid transporter SLC3A2 acts as a polyamine exporter in colon cancer-derived cells. Polyamine uptake is mediated by caveolin-1 dependent -endocytosis. The K-RAS oncogene signals increased polyamine uptake and decreased polyamine export. Here, we describe the methods of polyamine transport analysis in the colon and the small intestine using -membrane vesicles, culture cells, and mouse models.