UNC-13 and UNC-10/Rim localize synaptic vesicles to specific membrane domains
UNC-13 and UNC-10/Rim localize synaptic vesicles to specific membrane domains
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DOI：
10.1523/jneurosci.2350-06.2006
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发表时间：
2006-08-02
影响因子：
5.3
通讯作者：
Bessereau, Jean-Louis
中科院分区：
文献类型：
--
作者：
Weimer, Robby M.;Gracheva, Elena O.;Bessereau, Jean-Louis
突触小泡经历称为启动的成熟步骤，其中它们能够与质膜融合。为了从形态学上定义囊泡启动位点并识别具有融合能力的突触囊泡，我们将快速物理固定技术与免疫金染色和秀丽隐杆线虫神经肌肉接头处的高分辨率形态测量分析相结合。在这些突触前末梢中，突触小泡的子集在突触前致密投射的约 100 nm 范围内接触质膜。 UNC-13 是一种囊泡启动所需的蛋白质，定位于质膜的同一区域。在 unc-13 无效突变体中，很少有突触小泡接触质膜，这表明膜接触突触小泡代表了引发小泡的形态相关性。有趣的是，位于致密投影 30 nm 范围内的膜接触囊泡亚群在 unc-13 突变体中不受干扰。我们发现，UNC-10/Rim（一种与突触前可塑性有关的蛋白质）定位于致密投影，并且 UNC-10/Rim 的缺失会导致致密投影 30 nm 内膜接触突触小泡的独立于 UNC-13 的减少。我们的数据共同确定了 100 nm 密集投影内囊泡启动的离散域，并进一步表明 UNC-10/Rim 和 UNC-13 分别有助于该域内突触囊泡的膜定位。
Synaptic vesicles undergo a maturation step, termed priming, in which they become competent to fuse with the plasma membrane. To morphologically define the site of vesicle priming and identify fusion-competent synaptic vesicles, we combined a rapid physical-fixation technique with immunogold staining and high-resolution morphometric analysis at Caenorhabditis elegans neuromuscular junctions. In these presynaptic terminals, a subset of synaptic vesicles contact the plasma membrane within similar to 100 nm of a presynaptic dense projection. UNC-13, a protein required for vesicle priming, localizes to this same region of the plasma membrane. In an unc-13 null mutant, few synaptic vesicles contact the plasma membrane, suggesting that membrane-contacting synaptic vesicles represent the morphological correlates of primed vesicles. Interestingly, a subpopulation of membrane-contacting vesicles, located within 30nm of a dense projection, are unperturbed in unc-13 mutants. We show that UNC-10/Rim, a protein implicated in presynaptic plasticity, localizes to dense projections and that loss of UNC-10/Rim causes an UNC-13-independent reduction in membrane-contacting synaptic vesicles within 30 nm of the dense projections. Our data together identify a discrete domain for vesicle priming within 100 nm of dense projections and further suggest that UNC-10/Rim and UNC-13 separately contribute to the membrane localization of synaptic vesicles within this domain.