Prions by activation not amyloid

If conformational change can cause an infection—as appears to be the case with the amyloid-inducing prions—then perhaps the same is true for other protein modifications. B. Tibor Roberts and Reed Wickner (NIH, Bethesda, MD) now claim to have found an example of this latter case, and they suggest that the discovery of more cases is a matter of time.

Wickner says he knew “for 10 years” about work from Beth Jones (Carnegie Mellon University, Pittsburgh, PA), in which yeast cells lacking the upstream activator protease A (PrA) suffered a gradual disappearance of protease B (PrB) activity. This slow decline was always blamed on gradual dilution (even 10⁶-fold dilution) of PrA and PrB mRNAs and proteins, and inefficient autoactivation by PrB.

But now Roberts and Wickner show that PrB...