Ugbogu, E.A., Wippler, S., Euston, M., Kouwenhoven, E.N., Brouwer, A.P.M. de, Schweizer, L.M., Schweizer, M., Ugbogu, E.A., Wippler, S., Euston, M., Kouwenhoven, E.N., Brouwer, A.P.M. de, Schweizer, L.M., and Schweizer, M.
Item does not contain fulltext, The gene products of the five-membered PRS gene family in Saccharomyces cerevisiae have been shown to exist as three minimal functional entities, Prs1/Prs3, Prs2/Prs5, and Prs4/Prs5, each capable of supporting cell viability. The Prs1/Prs3 heterodimer can be regarded as the most important because its loss causes temperature sensitivity. It has been shown that the GFP signal generated by an integrated GFP-Prs1 construct is lost in the absence of Prs3. In addition to interacting with Prs3, Prs1 also interacts with Slt2, the MAPK of the cell wall integrity (CWI) pathway. Lack of the nonhomologous region (NHR1-1) located centrally in Prs1 abolished the temperature-induced increase in Rlm1 expression. Furthermore, in vitro point mutations generated in PRS1 corresponding to missense mutations associated with human neuropathies or in the divalent cation and/or 5-phosphoribosyl-1(alpha)-pyrophosphate binding sites also display increased Rlm1 expression at 30 degrees C and 37 degrees C and most give rise to caffeine sensitivity. Human PRPS1 cDNA cannot rescue the synthetic lethality of a prs1Delta prs5Delta strain because it lacks sequences corresponding to NHR1-1 of yeast Prs1. The correlation between caffeine sensitivity and increased basal expression of Rlm1 in the altered versions of PRS1 can be extended to their inability to rescue the synthetic lethality of a prs1Delta prs5Delta strain implying that impaired CWI may contribute to the observed loss of viability.