English: HCA shares fast retrogradely transported organelles with the neurotrophin receptor p75NTR. Motor neurons seeded in MFC were incubated for 30 min at 37°C with fluorescent HCA (red) and a fluorescently-labeled antibody against p75NTR (green) in resting conditions, then washed and imaged. Both HCA and the antibody have been added to the axonal side only of the MFC. The two channels are merged in the movie. Yellow structures indicate double positive organelles. Cell body is out of view on the right. Frames were taken every 3 s and played at 5 frames/s. This movie is a representative example of experiments performed on two independent primary motor neuron cultures.