The cellular and subcellular distribution of protein I, a major brain phosphoprotein, has been studied in the peripheral nervous system. The levels of protein I in various peripheral nerves and innervated peripheral tissues were determined by radioimmunoassay and radioimmunolabeling of polyacrylamide gels. The results indicated tha protein I is present throughout the peripheral nervous system. Denervation studies of adrenal medulla and iris suggested that the protein I contained in peripheral tissues is localized to the neuronal elements innervating those tissues. Protein I was found to be enriched in neurotransmitter vesicle fractions of peripheral nervous tissue. Moreover, protein I appeared to be transported from cell bodies to axons terminals at least partly in association with neurotransmitter vesicles.

Fried, G., Nestler, E. J., De Camilli, P., Stjärne, L., Olson, L., Lundberg, J. M., Hökfelt, T., Ouimet, C. C., & Greengard, P. (1982). Cellular and subcellular localization of protein I in the peripheral nervous system. Proceedings of the National Academy of Sciences, 79(8), 2717–2721.