Is there some way to experimentally determine the density distribution of Kinesin and Dynein in a Neuron? Fluorescence labeling would be impossible(?) as GFP markers would probably alter the motor dynamics. Any ideas? Or do any studies exist which looked into this topic?
It is possible to tag molecular motors with fluorescent proteins. It may impede with its movement but as this paper describes, a variant can be created that doesn't have cargo binding ability.
However, if your objective is just to determine the density distribution of Kinesin and Dynein in a Neuron, you can simply fix the cells and do IHC staining for the motor proteins followed by high resolution imaging.