Welcome to the PrionHome. This is a sequence database that keeps track of the ever-expanding
universe of prions and prion-like phenomena, and their families of related sequences.
For more information, see The PrionHome Project. To download from the database,
go to either Search or Browse. If you wish to contribute your own data, or suggest
changes and improvements, please go to Feedback / Submit Data. Please note that a major database update is released once a year, so there may be a lag of several months before new important data appears here.
On the right is a PrionHome news window, which lists minor updates, and changes to the database.
On the left are various convenient lists of Database entries, grouped according to 'Organism', 'Prion Name', etc. To access these, please click on the relevant button. Particularly useful are the lists of database entries by PrionHome Classification.
There are eight different PrionHome Classifications.The first four are derived from experimental observations. The second four are derived from sequence analysis. The classifications are as follows:
Prion proteins form prions. Currently here, we define a prion as any unit of propagation of an altered state of a protein or proteins. The prions are propagated by infection into organisms; or, for single-celled organisms, by donation of cellular non-genetic material. In the receiving organisms, the prions are propagated through co-option of homologs of the infecting protein(s), that may or may not be transgenic homologs.
If you want a file of prion proteins:
For a file in FASTA format, click here.
For a file in PrionHome Database format, click here. The PrionHome Database format is explained here.
These files comprise all metazoan protein sequences that have been shown to form prions, as well as all of the fungal prion sequences.
Transcellular Prionoid: For this database, this is defined as a protein with a prion-like altered state, which demonstrates cell-to-cell prion-like propagation, in a disease context. Here, we restrict this definition to proteins from multicellular organisms.
Quasi-Prion: A protein that has some behaviour like a prion, but does not fit the definition of prion or transcellular prionoid.
Interactor: Proteins shown to interact with a prion protein.
Ortholog: An ortholog of a protein that is known to form prions. Orthologs are the mutually most similar proteins in different organisms. In this database, vertebrate orthologs are also supported by gene synteny in the genomic DNA, where available.
Paralog: A paralog of a sequence that is known to form prions. Paralogs are protein/gene duplications within the same genome.
Pseudogene: A copy of a prion-related gene that is formed via retrotransposition, or other processes of duplication, followed by coding-sequence disablement.
Candidate-Prion: A protein sequence that contains a candidate prion domain in budding yeast, that has not yet been shown to be prion experimentally. Candidate prions have two categories:
(i) N/Q-biased: They have domains with an obvious bias for glutamine and/or asparagine residues, with optional contributing biases for glycine, serine and tyrosine, and biases against charged and hydrophobic residues, as observed in the first four described yeast prions. All known amyloid-based prions in budding yeast have regions that have glutamine/asparagine compositional bias.
(ii) Alberti-HMM: They have prion-like composition predicted by the HMM algorithm used in Alberti, et al. (2009) [Cell (2009); 137:146-58], trained on the first four described yeast prion determinants.
This is a rotating sample of images of structures of proteins included in the PrionHome database