Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Postersession I
BP 9.39: Poster
Montag, 12. März 2018, 17:30–19:30, Poster A
Modelling the Single Photon Response in Rods — •Charlotte J. Beelen1, Karl-Wilhelm Koch1, and Daniele Dell’Orco2 — 1Dept. Neuroscience, Biochemistry, University of Oldenburg — 2Department of Neurosciences, Biomedicine and Movement Sciences, Sect. of Biological Chemistry, University of Verona
Rod cells are responsible for vision in dim light. After the activation of the pigment molecule rhodopsin, a complex signal transduction cascade leads to an electrical signal, which can then be transmitted further through the retina. This phototransduction cascade can be modelled using differential equations for the molecular species involved, mainly with mass-action kinetics [1,2]. The model can reproduce rods’ behaviour across a vast range of experiments and mutations.
Rod cells are extremely sensitive: they have a reproducible response to single photons, thus operating at the physical sensing limit [3]. It is astonishing that the response to a single photon is very uniform, since a fluctuating signal would be expected.
To explain the uniformness of the single photon response and investigate which reactions are essential for its reproducibility, we modify the deterministic model of the phototransduction cascade in rods to also include stochasticity and spontaneous activation of the effector. We investigate how the reproducibility of the single photon response comes about and study the effect of multiple phosphorylations of rhodopsin.
[1] D. Dell’Orco et al, Mol. BioSyst. 5 1232-1246 (2009)
[2] B.M. Invergo et al, Mol. BioSyst. 10 1481-1489 (2014)
[3] R.D. Hamer et al, J. Gen. Physiol. 122 419-444 (2003)