Build or destroy? Investigating how plants connect protein synthesis and degradation to regulate protein quality control

Proteins are essential components of cells, and the proteome must be effectively regulated to maintain cellular integrity. A critical contributory step to proteome function is protein synthesis, where mRNAs are translated into polypeptides by the ribosome. However, problems can arise during this process, leading to the production of "bad" proteins that negatively impact cellular function. Defective mRNAs and proteins must be recognised and destroyed, but, surprisingly, mechanisms controlling co-translational protein quality in plants are still largely unknown.

We recently identified a family of E3 ubiquitin ligases in the model plant Arabidopsis that function at the interface of mRNA translation and protein destruction. This project will investigate the hypothesis that these ligases are components of an expanded and plant-specific “toolkit” that provides dynamic and stress-responsive functions in translational quality control. There are several key areas where a PhD candidate would focus their investigations:

(1) Defining how these E3 ligases dynamically associate with ribosomes, proteasomes and other cellular machineries to form ‘translasomes’ that act as quality surveillance hubs.

(2) Characterising their direct proteolytic and mRNA targets.

(3) Characterising how their activity is regulated in response to changing translational demands of the cell under optimal and challenged situations.

(4)Determining how they contribute to the control of global and stress-responsive mRNA translation and degradation.

The research will be largely molecular based and will also include ‘omics’ approaches. The PhD candidate will therefore gain expertise in a wide range of cutting edge and transferable techniques.