- The small GTP-binding protein, Rab6p, is associated with both Golgi and post-Golgi synaptophysin-containing membranes during synaptogenesis of hypothalamic neurons in culture. Tixier-Vidal, A., Barret, A., Picart, R., Mayau, V., Vogt, D., Wiedenmann, B., Goud, B. J. Cell. Sci. (1993)