Prion deadliness tied to division

In a finding that may help explain why some conformations of misfolded proteins cause diseases, while others don't, researchers report in this week's Nature that the virulence of prions appears to be rooted in their ability to break apart and generate new seeds. These findings fly in the face of previous assumptions that prion virulence was linked to faster growth, the authors note."It's a surprising finding," Guiseppe Legname, from the University of California in San Francisco, who did not participate in the study, told The Scientist. "But then afterwards when you think of it, it makes sense."Working in yeast, the researchers charted the differences between three different conformations of the same prion protein, and found that the strain with the most marked physiologic effects showed relatively slow growth. However, it was significantly more "brittle," causing the protein to easily divide and generate new seeds. A similar mechanism of...