More than 20 human diseases are related to protein misfolding which causes 
formation of amyloids, fibrillar aggregates of normally soluble proteins. Such 
diseases are called amyloid diseases or amyloidoses. Of them only prion diseases 
are transmissible. Amyloids of the prion type are described in lower eukaryotes. 
However, in contrast to mammalian prions, which cause incurable 
neurodegenerative diseases, prions of lower eukaryotes are related to some 
non-chromosomally inherited phenotypic traits. Here we summarize the results of 
studies of prions of the yeast Saccharomyces cerevisiae and of the use of yeast 
model for investigation of some human amyloidoses, such as prion diseases, 
Alzheimer's, Parkinson's, and Huntington's diseases.