A protein required for prion generation: [URE3] induction requires the Ras-regulated Mks1 protein.

نویسندگان

  • H K Edskes
  • R B Wickner
چکیده

Infectious proteins (prions) can arise de novo as well as by transmission from another individual. De novo prion generation is believed responsible for most cases of Creutzfeldt-Jakob disease and for initiating the mad cow disease epidemic. However, the cellular components needed for prion generation have not been identified in any system. The [URE3] prion of Saccharomyces cerevisiae is an infectious form of Ure2p, apparently a self-propagating amyloid. We now demonstrate a protein required for de novo prion generation. Mks1p negatively regulates Ure2p and is itself negatively regulated by the presence of ammonia and by the Ras-cAMP pathway. We find that in mks1Delta strains, de novo generation of the [URE3] prion is blocked, although [URE3] introduced from another strain is expressed and propagates stably. Ras2(Val19) increases cAMP production and also blocks [URE3] generation. These results emphasize the distinction between prion generation and propagation, and they show that cellular regulatory mechanisms can critically affect prion generation.

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عنوان ژورنال:
  • Proceedings of the National Academy of Sciences of the United States of America

دوره 97 12  شماره 

صفحات  -

تاریخ انتشار 2000