Membrane Binding of Parkinson's Protein α-Synuclein: Effect of Phosphorylation at Positions 87 and 129 by the S to D Mutation Approach |
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Authors: | Pravin Kumar Nathalie Schilderink Vinod Subramaniam Martina Huber |
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Affiliation: | 1. Department of Physics, Huygens-Kamerlingh-Onnes Laboratory, Leiden University, Leiden, The Netherlands;2. Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands;3. Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
FOM Institute AMOLF, Amsterdam, The Netherlands
Vrije Universiteit of Amsterdam, Amsterdam, The Netherlands |
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Abstract: | Human α-synuclein, a protein relevant in the brain with so-far unknown function, plays an important role in Parkinson's disease. The phosphorylation state of αS was related to the disease, prompting interest in this process. The presumed physiological function and the disease action of αS involves membrane interaction. Here, we study the effect of phosphorylation at positions 87 and 129, mimicked by the mutations S87A, S129A (nonphosphorylated) and S87D, S129D (phosphorylated) on membrane binding. Local binding is detected by spin-label continuous-wave electron paramagnetic resonance. For S87A/D, six positions (27, 56, 63, 69, 76, and 90) are probed; and for S129A/D, three (27, 56, and 69). Binding to large unilamellar vesicles of 100 nm diameter of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine in a 1 : 1 composition is not affected by the phosphorylation state of S129. For phosphorylation at S87, local unbinding of αS from the membrane is observed. We speculate that modulating the local membrane affinity by phosphorylation could tune the way αS interacts with different membranes; for example, tuning its membrane fusion activity. |
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Keywords: | alpha synuclein phosphorylation membrane binding EPR spectroscopy |
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