| First Author | Taylor DR | Year | 2005 |
| Journal | J Cell Sci | Volume | 118 |
| Issue | Pt 21 | Pages | 5141-53 |
| PubMed ID | 16254249 | Mgi Jnum | J:102391 |
| Mgi Id | MGI:3607441 | Doi | 10.1242/jcs.02627 |
| Citation | Taylor DR, et al. (2005) Assigning functions to distinct regions of the N-terminus of the prion protein that are involved in its copper-stimulated, clathrin-dependent endocytosis. J Cell Sci 118(Pt 21):5141-53 |
| abstractText | The cellular prion protein (PrP(C)) is essential for the pathogenesis and transmission of prion diseases. Although PrP(C) is known to be located in detergent-insoluble lipid rafts at the surface of neuronal cells, the mechanism of its internalisation is unclear, with both raft/caveolae-based and clathrin-mediated processes being proposed. We have investigated the mechanism of copper-induced internalisation of PrP(C) in neuronal cells by immunofluorescence microscopy, surface biotinylation assays and buoyant sucrose density gradient centrifugation in the presence of Triton X-100. Clathrin-mediated endocytosis was selectively blocked with tyrphostin A23, which disrupts the interaction between tyrosine motifs in the cytosolic domains of integral membrane proteins and the adaptor complex AP2, and a dominant-negative mutant of the adaptor protein AP180. Both these agents inhibited the copper-induced endocytosis of PrP(C). Copper caused PrP(C) to move laterally out of detergent-insoluble lipid rafts into detergent-soluble regions of the plasma membrane. Using mutants of PrP(C) that lack either the octapeptide repeats or the N-terminal polybasic region, and a construct with a transmembrane anchor, we show that copper binding to the octapeptide repeats promotes dissociation of PrP(C) from lipid rafts, whereas the N-terminal polybasic region mediates its interaction with a transmembrane adaptor protein that engages the clathrin endocytic machinery. Our results provide an experimental basis for reconciling the apparently contradictory observations that the prion protein undergoes clathrin-dependent endocytosis despite being localised in lipid rafts. In addition, we have been able to assign distinct functions in the endocytic process to separate regions of the protein. |
