Krumova P.,University of Gottingen |
Meulmeester E.,University of Gottingen |
Garrido M.,University of Gottingen |
Tirard M.,Max Planck Institute for Experimental Medicine |
And 14 more authors.
Journal of Cell Biology | Year: 2011
Posttranslational modification of proteins by attachment of small ubiquitin-related modifier (SUMO) contributes to numerous cellular phenomena. Sumoylation sometimes creates and abolishes binding interfaces, but increasing evidence points to another role for sumoylation in promoting the solubility of aggregationprone proteins. Using purified α-synuclein, an aggregation-prone protein implicated in Parkinson's disease that was previously reported to be sumoylated upon overexpression, we compared the aggregation kinetics of unmodified and modified α-synuclein. Whereas unmodified α-synuclein formed fibrils, modified α-synuclein remained soluble. The presence of as little as 10% sumoylated α-synuclein was sufficient to delay aggregation significantly in vitro. We mapped SUMO acceptor sites in α-synuclein and showed that simultaneous mutation of lysines 96 and 102 to arginine significantly impaired α-synuclein sumoylation in vitro and in cells. Importantly, this double mutant showed increased propensity for aggregation and cytotoxicity in a cell-based assay and increased cytotoxicity in dopaminergic neurons of the substantia nigra in vivo. These findings strongly support the model that sumoylation promotes protein solubility and suggest that defects in sumoylation may contribute to aggregationinduced diseases. © 2011 Krumova et al.
Alevra M.,University of Gottingen |
Alevra M.,German Research Foundation Research Center for Molecular Physiology of the Brain |
Schwartz P.,University of Gottingen |
Schild D.,University of Gottingen |
And 2 more authors.
PLoS ONE | Year: 2012
The diffusion coefficient of fluorescein in detached cilia of Xenopus laevis olfactory receptor neurons was measured using spatially-resolved FRAP, where the dye along half of the ciliary length was photobleached and its spatiotemporal fluorescence redistribution recorded. Fitting a one-dimensional numerical simulation of diffusion and photobleaching for 35 cilia resulted in a mean value of the diffusion coefficient (1.20±0.23)·10-10m2/s compared to free diffusion in aqueous solution. © 2012 Alevra et al.