"Our team has defined a second prion protein called 'Shadoo', that exists in addition to the well-known prion protein called 'PrP' " said Professor David Westaway, the Director of the Centre for Prions and Protein Folding Diseases at the university.
"For decades we believed PrP was a unique nerve protein that folded into an abnormal shape and caused prion disease: end of story. This view is no longer accurate," Westaway added.
This is the first discovery of a new brain prion protein since 1985. It is a result of the efforts made by collaborators from the University of Toronto, University of Alberta, Case Western Reserve University (Ohio) and the McLaughlin Research Institute (Montana).
"A second prion protein had been inferred by other research, based on indirect studies and the examination of DNA sequences. But we not only demonstrate that this theoretical protein really exists and shares several properties with healthy PrP; we have also defined an unexpected alteration in prion infections," said lead author Joel Watts, a graduate student at the University of Toronto's Centre for Research in Neurodegenerative Diseases.
"As the PrP molecule alters shape and accumulates in a prion-affected brain, the Shadoo protein seems to disappear," Watts added.
He further said that since proteins in a living cell are the molecules "that do the work, this is likely to be significant."
"Many facets of a prion disease like BSE are puzzling," Westaway said.
"The puzzles include the cause of death of brain cells, the function of normal prion proteins, and the rules governing emergence and spread of prions from animal to animal. We believe the Shadoo protein can give us a fresh purchase on these important questions," the researcher added.