e martë, shkurt 22, 2005

A Pathogenic PrP Mutation and Doppel Interfere with Polarized Sorting of

Several proteins linked to neurodegenerative diseases, such as the -amyloid precursor protein, amyloid -peptide, -secretase, and tau, undergo selective polarized sorting. We investigated polarized sorting of the mammalian prion protein (PrPC) and its homologue doppel (Dpl). In contrast to Dpl, which accumulates on the apical surface, PrPC is targeted selectively to the basolateral side in Madin-Darby canine kidney cells. An extensive deletion and domain swapping analysis revealed that the internal hydrophobic domain (HD) of PrP (amino acids 113–133) confers basolateral sorting in a dominant manner. PrP mutants lacking the HD are sorted apically, while Dpl chimeras containing the HD of PrP are directed to the basolateral membrane. Furthermore, a pathogenic PrP misse