1. Department of Biology, Institute of Molecular Cell Biology, and
2. Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, 48149 Münster, Germany
3. Center of Cellular Nanoanalytics Osnabrück, 49076 Osnabrueck, Germany
4. Cellular Communication Laboratory, Department of Biology and Chemistry, University of Osnabrueck, 49076 Osnabrueck, Germany