The Hsp90 of Candida albicans can confer Hsp90 functions in Saccharomyces cerevisiae: a potential model for the processes that generate immunogenic fragments of this molecular chaperone in C-albicans infections

During infections with a number of important eukaryotic pathogens the Hsp90 molecular chaperone of the pathogen is recognized as an immunodominant ant igen by the host immune system. Yeast molecular genetics should allow study of the extent of sequence variation within conserved immunodominant epitop es on pathogen Hsp90s that is compatible with essential Hsp90 functions, as well as the processes that generate antigenic subfragments of these Hsp90s , The Hsp90 of the fungal pathogen Candida albicans was shown in this study to provide both essential and nonessential (pheromone signalling and mamma lian steroid receptor activation) Hsp90 functions in Saccharomyces cerevisi ae cells. Much of the C. albicans Hsp90 expressed in respiratory S. cerevis iae cells was shown to undergo a partial degradation in vivo, a degradation that closely resembles that of the native Hsp82 (one isoform of the homolo gous Hsp90) in S. cerevisiae, Allowing for the differences in the length of the charged linker region between the N- and C-terminal domains of C. albi cans Hsp90 and S. cerevisiae Hsp82, these two proteins expressed in S. cere visiae appear to give the same major degradation products. These Hsp90 frag ments are similar to the products of incomplete Hsp90 degradation found in C. albicans cultures.