2008/2/3 0:00:00 C. elegans genome encodes only one gene of β-spectrin subunit (β-G), unc-70. Besides stabilizing plasma membranes and generating cell polarity, β-spectrin is also reported to mediate the secretary pathway. In the present studies, it was demonstrated that UNC-70 is involved in the dense core vesicle (DCV) exocytosis in C. elegans neurons. It was found that unc-70 dominant allele mutants exhibited reduced peptide release in vivo. In IDA-1 (related to islet cell diabetes autoantigen) labeled ALA neurons, which serve as a good model for studying DCV exocytosis, mutant of β-spectrin leads to visible reduction of the readily released pool (RRP) size. The analysis of vesicular docking by total internal reflection microscopy revealed that loss-of-function of unc-70 hindered the docking of DCVs in neurons. The electrophysiological experiments at the neuromuscular junctions excluded the possibility that the quantum size of acetylcholine in synaptic vesicles in neurous and postsynaptic response in muscle cells were affected. The above results provide evidences that β-spectrin is required for the exocytosis of DCVs and also possibly involved in the release of neurotransmitter.]]> 2009/9/16 0:00:00