Functional analysis of Rpn4-like proteins from Komagataella (Pichia) pastoris and Yarrowia lipolytica on a genetic background of Saccharomyces cerevisiae

Expression of the Saccharomyces cerevisiae proteasomal genes is regulated coordinately by ScRpn4 transcription factor and its binding site known as PACE. Genomic analysis demonstrates that only Saccharomycetes yeasts carry ScRpn4-orthologous genes and PACE-like elements in the promoters of proteasomal genes. This taxonomic group includes species of biotechnological importance such as Komagataella (Pichia) pastoris and Yarrowia lipolytica . A literature search has failed to identify studies focused on ScRpn4 orthologs of these yeast species. In the present work, using the genetic background of S. cerevisiae , we showed that ScRpn4 orthologs from K. pastoris and Y. lipolytica restore the mRNA levels of proteasomal genes and confer stress tolerance in a S. cerevisiae strain with knockout of the SCRPN4 gene. In other words, these proteins are functionally similar to ScRpn4 of S. cerevisiae .