Chapter category: Protein
Prion Stability
Protein-Based Inheritance
Edited by: Yury O. ChernoffISBN: 978-1-58706-138-7
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Chapter authors:
Brian S. Cox, Lee Byrne and Mick F. Tuite
The rate of spontaneous change from y- to the y+ condition determined in yeast by states of the Sup35p protein is briefly discussed, together with the conditions necessary for such change to occur. Conditions that promote and which affect the rate of induction of y+ in Sup35p and of other prion-forming proteins to their respective prion forms are also discussed. These include the influence of the amount of nonprion protein, the presence of other prions, the activity of chaperones, and brief descriptions of the role of native sequences in the proteins and how alteration of sequences in prion-forming proteins influence the rate of induction of [prion+] and amyloid forms. The second part of this article discusses the conditions which affect the reversion of y+ to y-, including factors which affect the copy-number of prion “seeds” or propagons and their partition. The principal factor discussed is the activity of the chaperone Hsp104, but the existence of other factors, such a protein sequence and of other, less well-studied agents, is touched upon and comparisons are made, as appropriate, with studies with other yeast prions. We conclude with a discussion of models of maintenance, in particular that of Tanaka et al. recently published in Nature (2006),6 which provides much insight into the phenotypic and genetic parameters of the numerous “variants” of prions increasingly being described in the literature.
Brian S. Cox
University of Kent
Lee Byrne
Mick F. Tuite
University of Kent
Additional chapters from this book:
Yeast Prions: Evolution of the Prion Concept
Reed B. Wickner, Herman K. Edskes, Frank Shewmaker, Toru Nakayashiki, Abbi Engel, Linsay McCann and Dmitry Kryndushkin
Prions (infectious proteins) analogous to the scrapie agent have been identified in Saccharomyces cerevisiae and Podospora anserina based on their special genetic character istics. Each is a prot...
A Short History of Small s: A Prion of the Fungus Podospora Anserina
Sven J. Saupe
Prions are infectious proteins. In fungi, prions correspond to non-Mendelian genetic elements whose mode of inheritance has long eluded explanation. The [Het-s] cytoplasmic genetic element of th...
Prion and Nonprion Amyloids: A Comparison Inspired by the Yeast Sup35 Protein
Vitaly V. Kushnirov, Aleksandra B. Vishnevskaya, Ilya M. Alexandrov and Michael D. Ter-Avanesyan
Yeast prion determinants are related to polymerization of some proteins into amyloid-like fibers. The [PSI+] determinant reflects polymerization of the Sup35 protein. Fragmen- tation of prion pol...
Biological Roles of Prion Domains
Sergey G. Inge-Vechtomov, Galina A. Zhouravleva and Yury O. Chernoff
In vivo amyloid formation is a widespread phenomenon in eukaryotes. Self-perpetuating amyloids provide a basis for the infectious or heritable protein isoforms (prions). At least for some protei...
Preformed Cell Structure and Cell Heredity
Janine Beisson
This chapter will first recall the phenomena of “cortical inheritance” observed and genetically demonstrated in Paramecium 40 years ago, and later in other ciliates (Tetrahymena, Oxytricha, Para...
Chaperone Effects on Prion and Nonprion Aggregates
Eugene G. Rikhvanov, Nina V. Romanova and Yury O. Chernoff
Exposure to high temperature or other stresses induces a synthesis of heat shock proteins. Many of these proteins are molecular chaperones, and some of them help cells to cope with heat-induced ...
Prion Stability
Brian S. Cox, Lee Byrne and Mick F. Tuite
The rate of spontaneous change from y- to the y+ condition determined in yeast by states of the Sup35p protein is briefly discussed, together with the conditions necessary for such change to occ...
Prion-Prion Interactions
Irina L. Derkatch and Susan W. Liebman
The term prion has been used to describe self-replicating protein conformations that can convert other protein molecules of the same primary structure into its prion conformation. Several differ...
The Genetic Control of the Formation and Propagation of the [PSI+] Prion of Yeast
Mick F. Tuite and Brian S. Cox
It is over 40 years since it was first reported that the yeast Saccahromyces cerevisiae contains two unusual cytoplasmic ‘genetic’ elements: [PSI+] and [URE3]. Remarkably the underlying determin...
Centriole Inheritance
Patricia G. Wilson
Early cell biologists perceived centrosomes to be permanent cellular structures. Centrosomes were observed to reproduce once each cycle and to orchestrate assembly of a transient mitotic apparat...
