Axis 3 - Exploring the UPR pathway in relation to protein maturation

The various stages of protein maturation and folding involve glycosylations and the formation of disulfide bridges that begin in the endoplasmic reticulum (ER). These processes can be impacted by environmental conditions, such as high temperatures, and can alter protein maturation, leading to a modification of the gluten network. When the ER is stressed by too many malformed proteins, a cellular regulation pathway, called the Unfolded Protein Response (UPR), is activated. The objective is to study the involvement of this pathway in the maturation of storage proteins. To do this, we are evaluating the level of expression of the UPR pathway genes in lines that are contrasted for the size of the polymers that will be identified (GlutNSafe FSOV project). Eventually, these genes could serve as biomarkers for phenotyping the effect of high temperatures on the maturation of storage proteins.

In eukaryotes, it is estimated that about 1/3 of the total protein corresponds to secreted or membrane proteins. The synthesis of this class of proteins begins in the cytoplasm and continues in the endoplasmic reticulum (ER) where these proteins undergo correct maturation and folding steps. Abiotic stresses, such as heat stress, lead to an accumulation of unfolded or misfolded proteins leading to ER stress. In response to this stress, the cell reacts, on the one hand by increasing the production of chaperone proteins and on the other hand by limiting the flow of proteins arriving in the ER via a proteolysis phenomenon called ER-Associated-Degradation (ERAD).