Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 3: Membranes and Interfaces
BP 3.11: Vortrag
Montag, 26. März 2007, 16:45–17:00, H43
Dynamics of IP3 receptor clustering on the endoplasmic reticulum — •Ronny Straube1,2, Martin Falcke1, and Michael Ward3 — 1Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin, Germany — 2Max-Planck-Institut für Dynamik komplexer technischer Systeme, Sandtorstr. 1, 39106 Magdeburg, Germany — 3Department of Mathematics, University of British Columbia, Vancouver, Canada
Motivated by the observation that IP3 receptor channels (IP3R) form clusters on the endoplasmic reticulum (ER) during ATP-induced calcium release [1], we calculate the reation rate of small diffusing molecules on a cylindrical membrane by taking into account the cylindrical topology of the tubular ER [2]. The reaction rate is obtained using the method of matched asymptotic expansions. For realistic parameter sets, our calculation predicts clustering rates in the experimentally observed range. Furthermore, it reveals how the cluster rate depends on the relevant system parameters such as the molecule size and the aspect ratio of the membrane. Based on our calculations of the reaction rate, we also study the dynamics of IP3R clustering as it is triggered by an external calcium signal. A mean-field approach is used to determine the temporal evolution of the cluster-size distribution.
[1] Y. Tateishi et. al., Cluster formation of inositol 1,4,5-triphosphate receptor requires its transition to open state, J. Biol. Chem. 280(8), 6816-6822 (2005).
[2] R. S., Michael J. Ward and Martin Falcke, Reaction rate of small diffusing molecules on a cylindrical membrane, submitted to J. Stat. Phys.