STRUCTURAL AND FUNCTIONAL SIMILARITY OF SUP35P AND URE2P YEAST PROTEINS AND MAMMALIAN PRIONS

Data concerning extrachromosomally inherited determinants [URE3] and [ psi] from Saccharomyces cerevisiae were summarized. Tandem amino acid repeats of similar structure were found in the N-terminal regions of y east Sup35 protein and prions of higher eukaryotes. A hypothesis conce rning prion-like properties of yeast Sup35 and Ure2 proteins and role of N-terminal tandem repeats of the Sup35 protein in the mechanism of [psi] inheritance is discussed. It is suggested that the [psi(+)] stat us of the cell depends on the specific conformation of the N-terminaI domain of Sup35p; the protein can induce this conformation in its de n ovo synthesized molecules via protein-protein interaction, thereby mai ntaining the [psi(+)] phenotype in further generations. Basing on the data on the existence of amino acid repeats similar to those of prions in other proteins, it is hypothesized that such proteins may have pri on-like properties.