RABV and mGluR2 are internalized into cells and transported together in early and late endosomes.

N2a Cells were stained by using the Tyramide Signal Amplification immunofluorescent method. Absence of co-localization of tubulin (green), Rab7 (red), and Tomm20 (purple) served as a negative control for co-localization (A and B). Significant co-localization of the mitochondrial marker AIF (green) and Tomm20 (red) served as a positive control for co-localization (C and D). N2a cells infected with ERA-N-mCherry for 20 minutes at 37°C were used to perform immunofluorescence staining for RABV antigen (red), mGluR2 (green), Rab5 or Rab7 (purple), and the cell nuclei (blue). Co-localization of the RABV-mGluR2 complex with Rab5 (E, F) or Rab7 (H, I) was observed and counted. The images, comprising three single fluorescence channels (G, J), represent amplified random co-localization spots in the merged image within the small white box (G from E, F from J). The 3D-rendered images were generated by using Imaris software (G, J) and the co-localization of the RABV-mGluR2 complex with Rab5 (G) or Rab7 (J) from the three single fluorescence channels is indicated with the white arrowhead.