datum	22.4.2014
přednáší	mw. dr. C.S. Christa Testerink (University of Amsterdam, Swammerdam Institute for Life Sciences)
název	Take it or leave it: cellular signaling pathways linking salinity stress to root growth
anotace	Plants have the ability to quickly respond to changes in their environment. To deal with drought, high salinity, or nutrient deprivation, plants adjust and optimize their root system architecture. We study the intracellular signalling pathways linking these stress conditions to root development and direction of root growth. One of the first reactions of plants to salt or drought is to change the phospholipid composition of cellular membranes. This in turn triggers a cascade of intracellular signaling that eventually leads to acclimatization, thereby promoting survival. Phosphatidic acid (PA) is a signaling lipid that rapidly accumulates in response to a wide array of abiotic stress stimuli. Its formation provides the cell with spatial and transient information about the external environment, by acting as a protein-docking site in cellular membranes. Previously, we have isolated and identified several proteins that directly interact with PA. Functional characterization of two PA-binding SNF1-related protein kinases (SnRK2s) revealed that they are involved in maintaining root growth and branching under salinity stress. In addition, we set up an approach to specifically isolate and identify putative proteins from Arabidopsis roots that interact with PA and are recruited to membranes in response to salt. Proteins identified act in the regulation of potassium homeostasis, general metabolism and clathrin recruitment, amongst other functions. In accordance, phospholipase D-generated PA formation was found to be essential for clathrin-mediated endocytosis as an immediate response to salinity. I will discuss implications of this pathway for directional growth of roots away from high salinity, which involves redistribution of auxin, and occurs through clathrin-mediated internalization, but not degradation, of the auxin efflux carrier PIN2.
materiály	životopis přednášejícího

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