Effects of plant metabolites on unfolded protein response in yeast

Abstract

The unfolded protein response is a survival adaptation involving a stress response pathway at the endoplasmic reticulum. Accumulation of misfolded protein misfolding, as one of the sources of ER stress, activates one or more of the three UPR transducers and their downstream signalling pathways to suppress protein production while facilitating the folding of proteins and proteasomal degradation of misfolded proteins to re-establish protein homeostasis. Furthermore, the UPR is closely tied to protein-misfolding diseases, notably neurodegenerative diseases such as the Alzheimer’s disease and Parkinson’s disease. Tea drinking has long been touted to be able to delay or even prevent the onset of such diseases, generating much research interest. In this study, I make use of the leaves from different plant species, the key ingredient of tea, to deduce if their metabolites play any role in UPR, specifically the inositol-requiring enzyme 1 (Ire1) pathway, in S. cerevisiae yeast. Following the extraction of plant metabolites, wild-type and ire1Δ yeast strains were grown with increasing extract concentration and their growth rates were used to deduce if they activated UPR or played a mitigating role, through which metabolites from several plant species were found to demonstrate.