PRION PROTEIN PRPC INTERACTS WITH MOLECULAR CHAPERONES OF THE HSP60 FAMILY

Prions mediate the pathogenesis of certain neurodegenerative diseases, including bovine spongiform encephalopathy in cattle and Creutzfeldt- Jakob disease in humans. The prion particle consists mainly, if not en tirely, of PrPSc, a posttranslationally modified isoform of the cellul ar host-encoded prion protein (PrPc), It has been suggested that addit ional cellular factors might be involved in the physiological function of PrPc and in the propagation of PrPSc, Here we employ a Saccharomyc es cerevisiae two-hybrid screen to search for proteins which interact specifically with the Syrian golden hamster prion protein, Screening o f a HeLa cDNA library identified heat shock protein 60 (Hsp60), a cell ular chaperone as a major interactor Tor PrPc. The specificity of the interaction was confirmed in vitro for the recombinant proteins PrP(c) 23-231 and rPrP27-30 fused to glutathione S-transferase with recombina nt human Hsp60 as well as the bacterial GroEL, Tile interaction site f or recombinant Hsp60 and GroEL proteins,vas mapped between amino acids 180 and 210 of the prion protein by screening with a set of recombina nt PrPc fragments, The binding of Hsp60 and GroEL occurs within a regi on which contains parts of the putative alpha-helical domains H3 and H 4 of the prion protein.