HeLa cells (ATCC) were transfected with constructs expressing, TNFR1 fluorescent fusion proteins, a DsRed2-tagged beta subunit of the signal particle receptor (SRβ) as a marker of the ER, and an ECFP-tagged trans-Golgi-resident protein N-acetylgalactosaminyltransferase-2 (GalNAc-T2) stalk region as a marker of the Golgi. TO-PRO®-3 iodide (Molecular Probes, Invitrogen) was used for nuclear staining, with staining being performed 48 h after transfection. Images were taken with an LSM510 confocal microscope (Zeiss) and processed using Zeiss LSM510 v.3.2 and Image J software. Colocalization was quantified using MetaMorph software (Molecular Devices).
