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Publikation Photoconversion and nuclear trafficking cycles determine phytochrome A's response profile to far-red light(Cell Press, 02.09.2011) Rausenberger, Julia; Tscheuschler, Anke; Nordmeier, Wiebke; Wüst, Florian; Timmer, Jens; Schäfer, Eberhard; Fleck, Christian; Hiltbrunner, AndreasPhytochrome A (phyA) is the only photoreceptor in plants, initiating responses in far-red light and, as such, essential for survival in canopy shade. Although the absorption and the ratio of active versus total phyA are maximal in red light, far-red light is the most efficient trigger of phyA-dependent responses. Using a joint experimental-theoretical approach, we unravel the mechanism underlying this shift of the phyA action peak from red to far-red light and show that it relies on specific molecular interactions rather than on intrinsic changes to phyA's spectral properties. According to our model, the dissociation rate of the phyA-FHY1/FHL nuclear import complex is a principle determinant of the phyA action peak. The findings suggest how higher plants acquired the ability to sense far-red light from an ancestral photoreceptor tuned to respond to red light.01A - Beitrag in wissenschaftlicher Zeitschrift