Effect of Chaperones on Prion Protein PrP23-98 Aggregation In Vitro

Recent studies have indicated that PrP23-98, an N-terminal portion of PrP, polymerizes into amyloid-like and proteinase K (PK)-resistant aggregates in the presence of NADPH with copper ions [19], and then that CRT suppressed aggregation of PrP23-98 and also promoted solubilization of the aggregates [18]. As it is interesting to find out whether other chaperones can inhibit aggregation of PrP23-98 in vitro similar to CRT, this study was conducted to determine whether BiP, Grp94, PDI Grp58 and heat shock cognate protein70 (Hsc70) can inhibit aggregation of PrP23-98 in vitro. The present results indicated that Grp94 suppressed aggregation of PrP23-98, but that Grp94 could not mediate solubilization occurred in the aggregates in contrast to CRT. Other chaperons induced aggregation of PrP23-98 in the absence of NADPH.