Involvement of Ca2+ Channel Synprint Site in Synaptic Vesicle Endocytosis
Involvement of Ca2+ Channel Synprint Site in Synaptic Vesicle Endocytosis
复制标题
DOI：
10.1523/jneurosci.3214-09.2010
复制
发表时间：
2010-01
期刊：
影响因子：
--
通讯作者：
Hiroyasu Watanabe;Takayuki Yamashita;N. Saitoh;Shigeki Kiyonaka;A. Iwamatsu;K. Campbell;Y. Mori;Tomoyuki Takahashi
中科院分区：
文献类型：
--
作者：
Hiroyasu Watanabe;Takayuki Yamashita;N. Saitoh;Shigeki Kiyonaka;A. Iwamatsu;K. Campbell;Y. Mori;Tomoyuki Takahashi
电压门控 Ca2+ 通道 (VGCC) α1 亚基的突触蛋白相互作用 (synprint) 位点可以与参与胞吐作用的蛋白质相互作用，因此被认为对于突触小泡的胞吐作用至关重要。在这里，我们报道，synprint位点还可以直接结合AP-2的μ亚基，AP-2是网格蛋白介导的内吞作用的接头蛋白，与突触结合蛋白1（Syt 1）C2B结构域竞争。在脑裂解物中，AP-2-synprint 相互作用发生在较宽的 Ca2+ 浓度范围内，但在高 Ca2+ 浓度下受到抑制，其中 Syt 1 与 synprint 位点相互作用。在大鼠脑干切片的 Held 突触花萼处，直接突触前加载 synprint 片段肽可阻断内吞膜电容变化，但不会阻断胞吐膜电容变化。我们提出，VGCC synprint 位点通过与 AP-2 和 Syt 的 Ca2+ 依赖性相互作用参与神经末梢的突触小泡内吞作用，而不是胞吐作用。
The synaptic protein interaction (synprint) site of the voltage-gated Ca2+ channel (VGCC) α1 subunit can interact with proteins involved in exocytosis, and it is therefore thought to be essential for exocytosis of synaptic vesicles. Here we report that the synprint site can also directly bind the μ subunit of AP-2, an adaptor protein for clathrin-mediated endocytosis, in competition with the synaptotagmin 1 (Syt 1) C2B domain. In brain lysates, the AP-2–synprint interaction occurred over a wide range of Ca2+ concentrations but was inhibited at high Ca2+ concentrations, in which Syt 1 interacted with synprint site. At the calyx of Held synapse in rat brainstem slices, direct presynaptic loading of the synprint fragment peptide blocked endocytic, but not exocytic, membrane capacitance changes. We propose that the VGCC synprint site is involved in synaptic vesicle endocytosis, rather than exocytosis, in the nerve terminal, via Ca2+-dependent interactions with AP-2 and Syt.