Two-Dimensional Interfacial Exchange Diffusion Has the Potential to Augment Spatiotemporal Precision of Ca2+ Signaling |
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Authors: | Cornelis van Breemen Nicola Fameli Klaus Groschner |
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Affiliation: | 1.Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada;2.Independent Researcher, Vancouver, BC V5Z 1R1, Canada;3.Gottfried Schatz Research Center—Division of Biophysics, Medical University of Graz, 8036 Graz, Austria |
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Abstract: | Nano-junctions between the endoplasmic reticulum and cytoplasmic surfaces of the plasma membrane and other organelles shape the spatiotemporal features of biological Ca2+ signals. Herein, we propose that 2D Ca2+ exchange diffusion on the negatively charged phospholipid surface lining nano-junctions participates in guiding Ca2+ from its source (channel or carrier) to its target (transport protein or enzyme). Evidence provided by in vitro Ca2+ flux experiments using an artificial phospholipid membrane is presented in support of the above proposed concept, and results from stochastic simulations of Ca2+ trajectories within nano-junctions are discussed in order to substantiate its possible requirements. Finally, we analyze recent literature on Ca2+ lipid interactions, which suggests that 2D interfacial Ca2+ diffusion may represent an important mechanism of signal transduction in biological systems characterized by high phospholipid surface to aqueous volume ratios. |
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Keywords: | Ca2+ signaling nano-junctions intermembrane nano-spaces Ca2+ transport Ca2+ lipid interaction surface diffusion |
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