Poster: Oxidative stress
Abs #
73: Comparative proteomics of the light stress response of the thylakoid membrane in chloroplasts of Arabidopsis thaliana wild-type and the ascorbate-deficient vtc2 mutant
An extensive characterization of the thylakoid proteome of Arabidopsis thaliana visualized the expression of a number of proteins, such as isomerases, chaperones, fibrillins, peroxiredoxins, m-type thioredoxins and ascorbate peroxidases. Together they form a complex network of activities in terms of stress defense, protein (un)folding, and repair in and around the thylakoid membrane. However, it is unclear to what extent their expression levels and activities are coordinated. These proteins were identified through a combination of different protein separation techniques, mass spectrometry and bioinformatics. A genome-wide screening using subcellular predictors identified additional proteins of this network. A public database with the identified thylakoid proteome is now available (http://cbsu.tc.cornell.edu/vanwijk).
Combining comparative proteomics techniques and A. thaliana mutants partially impaired in the oxidative stress defense system, we follow the differential expression of these proteins. This will provide insight in their contribution during stress response, as well as the consequences for the photosynthetic apparatus located in the thylakoid proteome.
Ascorbate is a water soluble antioxidant, which helps detoxification of reactive oxygen species produced in the chloroplast under stress conditions, such as excess of light. The A. thaliana vtc2-2 mutant has a reduced accumulation of ascorbate, and shows reduced non photochemical quenching under high light. In this poster, we present the differential expression of the thylakoid proteomes of wild-type and vtc2-2 during the transition from low to high light. Differential protein expression is determined by 2-dimensional gels and image analysis, followed by protein identification by mass spectrometry.
