Role of the Doc2α-Munc13-1 interaction in the neurotransmitter release process
Role of the Doc2α-Munc13-1 interaction in the neurotransmitter release process
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DOI：
10.1073/pnas.95.19.11418
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发表时间：
1998-09-15
影响因子：
11.1
通讯作者：
Takai, Y
中科院分区：
文献类型：
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作者：
Mochida, S;Orita, S;Takai, Y
Doc2α和Munc13-1蛋白分别高度集中在突触小泡和突触前质膜上，并参与钙依赖的神经递质释放。Doc2α通过Doc2α的N-末端区域(中间结构域，氨基酸残基13-37)与Munc13-1相互作用，在这里我们研究了Doc2α和Munc13-1之间的相互作用是否需要完整神经元释放钙依赖的神经递质。人工合成的Mid肽(Mid肽)在体外可抑制Doc2α与Munc13-1的相互作用，而不是对照突变的Mid肽或杂乱的Mid肽。将Mid肽引入大鼠颈上神经节神经元之间形成的胆碱能突触的突触前神经元中，可逆地抑制由动作电位引起的突触传递，而对照多肽不抑制突触传递。这种抑制作用依赖于突触前活动，并受细胞外钙离子浓度的影响。当刺激频率较高时，中肽效应的开始时间缩短，1 mM的钙离子的抑制作用强于5.1 mM的钙离子。这些结果表明，Doc2α-Munc13-1的相互作用在突触小泡与突触前质膜融合的最后一步中，在诱发的神经递质释放过程中起作用。
Doc2 alpha and Munc13-1 proteins are highly concentrated on synaptic vesicles and the presynaptic plasma membrane, respectively, and have been implicated in Ca2+-dependent neurotransmitter release, Doc2 alpha interacts with Munc13-1 through the N-terminal region of Doc2 alpha (the Mid domain; amino acid residues 13-37), Here we examine whether the interaction between Doc2 alpha and Munc13-1 is required for Ca2+-dependent neurotransmitter release from intact neuron. A synthetic Mid peptide (the Mid peptide), but not a control mutated Mid peptide or a scrambled Mid peptide, inhibited the interaction between Doc2 alpha and Munc13-1 in vitro. Introduction of the Mid peptide into presynaptic neurons of cholinergic synapses, formed between rat superior cervical ganglion neurons, reversibly inhibited synaptic transmission evoked by action potentials, In contrast, the control peptides did not inhibit synaptic transmission. This inhibitory effect depended on the presynaptic activity and was affected by extracellular Ca2+ concentrations. The onset of the Mid peptide effect was shortened when the neuron was stimulated at a higher frequency, and the inhibition was more potent at 1 mM Ca2+ than at 5.1 mM Ca2+. These results suggest that the Doc2 alpha-Munc13-1 interaction plays a role in a step before the final fusion step of synaptic vesicles with the presynaptic plasma membrane in the evoked neurotransmitter release process.