Snap-25 is polarized to axons and abundant along the axolemma: an immunogold study of intact neurons.

摘要: SNAP-25, synaptosomal associated protein of 25 kDa, is reported to be a t-SNARE (target receptor with the presynaptic plasma membrane) involved in docking and fusion synaptic vesicles. We present here first ultrastructural localization SNAP-25 intact neurons by pre-embedding EM immunocytochemistry rat brains, hippocampal slice cultures, PC12 cells. In differentiated neurons, labeling was clearly membrane-associated. The most prominent membrane axons excluded from membranes soma dendrites. Furthermore, did not appear restricted junctions. seen cytoplasm large dendrites, mostly Golgi complexes. There were also some labeled tubulo-vesicular structures axons, but rarely smaller cells, after 5-10 minutes high potassium (75 mM) stimulation presence HRP, appeared, additionally, on HRP-filled early endosomes. After longer (20-30 minutes) HRP incubation, later stage endosomes lysosomes loaded they negative for SNAP-25. These results suggest that sorted out these late endosomal compartments, bulk probably recycled back axolemma contrast, those samples which incubated periods, there still SNAP-25-positive vesicular HRP-negative. likely represent anterograde vesicles carry newly synthesized axonal transport. appears at complex reach specifically. Its widespread distribution all along does support view as limited exocytosis.