**2. Materials**

DC-30 was purchased from Avanti Polar Lipids (Birmingham, AL, USA). The Cy-5- and Rh-DNA Labeling Kits, Transferrin Alexa Fluor conjugate 488, Cholera Toxin Subunit B Alexa Fluor conjugate 488 and DAPI were purchased from Molecular Probes (Leiden, The Netherlands). Cells were purchased from ATCC (American Type Culture Collection),

Manassas, USA and pEGFP from BD Clontech Germany, Heidelberg. Unless otherwise stated, all other chemicals were purchased from Sigma/Fluka (Deisenhofen, Germany) and were of analytical grade. Additional material is described in the appropriate method section.
