BBSRC EASTBIO PhD Programme: Greasing plant signal transduction – how does reversible S-acylation regulate plant responses to pathogens?

Plants perceive extracellular physical stimuli, such pathogens, symbionts, hormones or cell wall stress, through Receptor-like kinases. Activation of Receptor-like kinases leads to intracellular signalling through multiple routes from the plasma membrane, cytoplasm and nucleus [1]. S-acylation is a lipid based post-translational modification known to regulate many aspects of protein function including affinity for membranes and membrane microdomains. By becoming de-S-acylated a protein will be able to move away from the membrane where it was activated, for example by a plasma membrane bound Receptor-like kinase, and carry a signal to another region of the cell such as the nucleus [2]. We recently found that inhibiting protein de-S-acylation blocks the activation of many of the pathways downstream of multiple Receptor-like kinases. This suggests that S-acylated proteins acting downstream of Receptor-like kinases is a general phenomenon and that their de-S-acylation is essential for their signal transduction functions.

As model systems to investigate this novel process you will use activation of the plant pathogen Receptor-like kinases FLS2 and EFR. You will initially take a quantitative proteomics approach [3] coupled with inhibitor treatment and biochemical enrichment of S-acylated proteins to identify the S-acylated proteins acting downstream of FLS2 and EFR activation in an unbiased manner. Once these proteins are identified you will characterize the role of reversible S-acylation in their function and examine how changes in S-acylation state determine their effects on particular signalling routes in the cell and the overall resistance of plants to pathogens. This will provide missing mechanistic information about how plants convert extracellular perception events into intracellular action leading to pathogen resistance.

To perform this work you will acquire expertise in quantitative proteomics, biochemical analysis of S-acylation, molecular biology, plant-pathogen interaction signalling, protein biochemistry, and generation of transgenic Arabidopsis.