High-speed imaging reveals the bimodal nature of dense core vesicle exocytosis.
High-speed imaging reveals the bimodal nature of dense core vesicle exocytosis.
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DOI：
10.1073/pnas.2214897120
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发表时间：
2023-01-03
影响因子：
11.1
通讯作者：
Edwards RH
中科院分区：
文献类型：
--
作者：
Zhang P;Rumschitzki D;Edwards RH
在胞吐过程中，囊泡与质膜融合形成一个孔，神经递质和多肽通过该孔被释放。这种融合孔的行为变化很大，影响了释放的含量、速率和程度。然而，这种变异通常被认为是随机的，这意味着缺乏生物控制。通过对单个致密核囊泡的高速胞吐成像，我们发现融合孔行为的变化涉及不同的机制。此外，我们确定了两类胞外事件，它们对突触蛋白7（钙传感器）的缺失有不同的反应。我们的结果提示了融合孔行为变化的生物学来源，并为指导未来机制的工作提供了框架。在胞吐过程中，分泌囊泡与质膜融合形成孔，调节神经递质和肽的释放。融合孔行为的非均匀性归因于共同胞吐机制的随机变化，这意味着缺乏生物控制。我们使用荧光假神经递质（FFN），在毫秒分辨率的全内反射荧光显微镜下对小鼠肾上腺染色质细胞的致密核囊泡（DCV）胞吐进行成像，观察到明显不同的释放模式，快速事件持续<30 ms，缓慢事件持续数秒。缓慢事件的双重成像显示，相对于FFN的释放，外部染料的进入延迟，表明被直径<1 nm的极窄孔排除在外。无偏综合分析表明，观察到的变化不能仅用随机性来解释，而是涉及不同的机制，揭示了DCV胞外分泌的双峰性。此外，钙传感器synaptotagmin 7的缺失增加了缓慢事件的比例，而不改变这两类的固有特性，表明可能存在独立调节。鉴定出两种不同的释放机制，能够独立调节，这表明融合孔行为的多样性具有生物学基础。
During exocytosis, vesicle fusion with the plasma membrane establishes a pore through which neurotransmitters and peptides are released. The behavior of this fusion pore varies widely, affecting the content, rate, and extent of release. However, this variation is usually considered stochastic, implying a lack of biological control. By imaging the exocytosis of individual dense core vesicles at high speed, we find that the variation in fusion pore behavior involves distinct mechanisms. Moreover, we identify two classes of exocytic event that respond differentially to the loss of synaptotagmin 7, a calcium sensor. Our results suggest a biological source for the variation in fusion pore behavior and provide a framework to guide future work on the mechanisms responsible. During exocytosis, the fusion of secretory vesicle with plasma membrane forms a pore that regulates release of neurotransmitter and peptide. Heterogeneity of fusion pore behavior has been attributed to stochastic variation in a common exocytic mechanism, implying a lack of biological control. Using a fluorescent false neurotransmitter (FFN), we imaged dense core vesicle (DCV) exocytosis in primary mouse adrenal chromaffin cells by total internal reflection fluorescence microscopy at millisecond resolution and observed strikingly divergent modes of release, with fast events lasting <30 ms and slow events persisting for seconds. Dual imaging of slow events shows a delay in the entry of external dye relative to FFN release, suggesting exclusion by an extremely narrow pore <1 nm in diameter. Unbiased comprehensive analysis shows that the observed variation cannot be explained by stochasticity alone, but rather involves distinct mechanisms, revealing the bimodal nature of DCV exocytosis. Further, loss of calcium sensor synaptotagmin 7 increases the proportion of slow events without changing the intrinsic properties of either class, indicating the potential for independent regulation. The identification of two distinct mechanisms for release capable of independent regulation suggests a biological basis for the diversity of fusion pore behavior.
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影响因子：
9.8
作者：
Jaiswal JK;Chakrabarti S;Andrews NW;Simon SM
通讯作者：
Simon SM
影响因子：
4
作者：
Hu G;Henke A;Karpowicz RJ Jr;Sonders MS;Farrimond F;Edwards R;Sulzer D;Sames D
通讯作者：
Sames D
影响因子：
64.8
作者：
Bao H;Das D;Courtney NA;Jiang Y;Briguglio JS;Lou X;Roston D;Cui Q;Chanda B;Chapman ER
通讯作者：
Chapman ER
DOI：
10.1523/jneurosci.3426-12.2013
发表时间：
2013-01-30
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
--
作者：
Chen M;Van Hook MJ;Zenisek D;Thoreson WB
通讯作者：
Thoreson WB
影响因子：
16.6
作者：
Chiang, Hsueh-Cheng;Shin, Wonchul;Zhao, Wei-Dong;Hamid, Edaeni;Sheng, Jiansong;Baydyuk, Maryna;Wen, Peter J.;Jin, Albert;Momboisse, Fanny;Wu, Ling-Gang
通讯作者：
Wu, Ling-Gang