We describe a method to label protein on the surface of living neurons using a specific polyclonal antibody to extracellular epitopes. Protein bound by the antibody on the cell surface and subsequently internalized via endocytosis can be distinguished from protein remaining on, or trafficked to, the surface during the incubation.
Carrodus, N. L., Teng, K. S., Munro, K. M., Kennedy, M. J., Gunnersen, J. M. Differential Labeling of Cell-surface and Internalized Proteins after Antibody Feeding of Live Cultured Neurons. J. Vis. Exp. (84), e51139, doi:10.3791/51139 (2014).