N-glycosylation is a potent regulator of prion protein neurotoxicity
Kevin M. Schilling, Pooja Jorwal, Natalia C. Ubilla‐Rodriguez, Tufa E. Assafa, Jean R.P. Gatdula, Janelle S. Vultaggio, David A. Harris, Glenn L. Millhauser
Abstract
The C-terminal domain of cellular prion protein (PrP C ) contains two N-linked glycosylation sites, the occupancy of which impacts disease pathology. In this study, we demonstrate that glycans at these sites are required to maintain an intramolecular interaction with the N-terminal domain, mediated through a previously identified copper-histidine tether, which suppresses the neurotoxic activity of PrP C . NMR and EPR spectroscopy demonstrate that the glycans refine the structure of the protein's interdomain interaction. Using whole-cell patch-clamp electrophysiology, we further show that cultured cells expressing PrP molecules with mutated glycosylation sites display large, spontaneous inward currents, a correlate of PrP-induced neurotoxicity. Our findings establish a structural basis for the role of N-linked glycans in maintaining a non-toxic, physiological fold of PrP C .