Structural and functional analysis of cytokinin-regulated DIRIGENT proteins from Arabidopsis thaliana

Our Research Group Functional Genomics and Proteomics of Plants has been investigating plant hormonal signaling pathways, particularly cytokinins and ethylene in the development of model plant Arabidopsis thaliana (1-4) for a long time. Recently, we have turned our attention to understand the molecular mechanisms mediating cytokinin regulations of the cell wall composition and thus its biomechanical properties. We found that two out of 26 Arabidopsis DIRIGENT proteins (AtDIR13 and AtDIR14) are up-regulated by cytokinins in the Arabidopsis roots and they also seem to be direct targets of cytokinin signaling (2). AtDIR6 is the only member of the family with known structure (5). DIRIGENT proteins are glycoproteins mediating biosynthesis of lignan and lignin, phenolic compounds important in plant development. Some DIRIGENT proteins were shown to be involved in the biotic and abiotic stress responses. Additionally, lignin that represents approx. 15-30% dry weight of lignocellulose has potential as a renewable source of high-value aromatic chemicals. Lignans can be used as drugs in conventional medicine. The aim of this work is to clone, express, purify and crystallize AtDIR13/14 proteins and use them in the series of in vitro enzymatic assays in order to identify their substrate specificity and putative role in the catalysis of lignin and/or lignan formation.
We expect: Highly motivated candidates with ambition of reaching top-ranked results. We offer: Experimental work on own project with the possibility of publication in distinguished international journals, nice lab staff, world-class lab equipment, attractive environment of novel university campus, help with both intellectual and practical problems, competitive salary corresponding to the work efficiency. Contact and further info: +420 5 4949 3029, [Email Address Removed], [Email Address Removed]

RG: Jan Hejátko Research Group

Keywords: cytokinin regulations, Arabidopsis DIRIGENT proteins,AtDIR13, AtDIR14, plant model Arabidopsis thaliana, hormonal signaling pathways

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