Propagation of the scrapie isoform of the prion protein (PrPSc) depends on the expression of endogenous cellular prion (PrPC). During oral infection, PrPSc propagates, by conversion of the PrPC to PrPSc, from the gastrointestinal tract to the nervous system. Intestinal epithelium could serve as the primary site for PrPC conversion. To investigate PrPC sorting in epithelia cells, we have generated both a green fluorescent protein (EGFP) or hernagglutinin (HA) tagged human PrPC (hPrP(C)). Combined molecular, biochemical, and single living polarized cell imaging characterizations suggest that hPrP(C) is selectively targeted to the apical side of Madin-Darby canine kidney (MDCKII) and of intestinal epithelia (Caco2) cells. (c) 2007 Elsevier Inc. All rights reserved.