Detection and imaging of zinc secretion from pancreatic β-cells using a new fluorescent zinc indicator
Detection and imaging of zinc secretion from pancreatic β-cells using a new fluorescent zinc indicator
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DOI：
10.1021/ja011774y
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发表时间：
2002-02-06
影响因子：
15
通讯作者：
Kennedy, R
中科院分区：
文献类型：
--
作者：
Gee, KR;Zhou, ZL;Kennedy, R
合成了一种新型的可见波长锌离子选择性荧光团（FluoZin-3，9）。该分子的螯合部分类似于已知的EGTA基Ca 2+选择性氟离子载体，除了在9中删除了一个N-乙酸部分。FluoZin-3在不存在Zn 2+的情况下几乎不发荧光，并且在用Zn 2+（约100 nM）饱和时表现出几百倍的荧光增加，aKd= 15 ± 2 nM。确定了9：Zn 2+的1：1结合化学计量比，并且在pH > 6时，络合物的荧光不依赖于pH。FluoZin-3用于监测在用葡萄糖刺激后通过胞吐作用从胰腺β细胞与胰岛素共分泌的Zn 2+。细胞附近的总Zn 2+浓度达到600 nM，并且在距离分泌细胞至少15 μm处可检测到Zn 2+。细胞间的异质性分泌表明，在一个集群中的一些细胞不释放Zn 2+。此外，在分泌细胞内，细胞膜的某些区域引起分泌，而其他区域则没有，这表明细胞表面上存在分泌的活性区。
A novel Zn2+-selective visible wavelength fluoroionophore (FluoZin-3,9) was synthesized. The chelating portion of the molecule resembles known EGTA-based Ca2+-selective fluoroionophores, except that one of the N-acetic acid moieties has been deleted in9. FluoZin-3 is virtually non-fluorescent in the absence of Zn2+, and exhibits a several hundred-fold fluorescence increase upon saturation with Zn2+(∼100 nM), with aKd= 15 ± 2 nM. A 1:1 binding stoichiometry of9:Zn2+was determined, and the fluorescence of the complex is pH-independent at pH > 6. FluoZin-3 was used to monitor Zn2+that was co-secreted with insulin from pancreatic β-cells by exocytosis following stimulation with glucose. The total Zn2+concentration near the cells reached 600 nM, and Zn2+was detectable at least 15 μm away from secreting cells. Heterogeneity in secretion among cells was indicated in that some cells in a cluster did not release Zn2+. Also, within secreting cells some regions of the cell membrane gave rise to secretion while others did not, suggesting active zones of secretion on the cell surface.