Protein kinase C modulates synaptic vesicle acidification in a ribbon type nerve terminal in the retina.
Protein kinase C modulates synaptic vesicle acidification in a ribbon type nerve terminal in the retina.
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DOI：
10.1016/j.neuint.2008.07.004
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发表时间：
2008-11
影响因子：
4.2
通讯作者：
Guatimosim, Cristina
中科院分区：
文献类型：
--
作者：
Abreu, Bento J.;Guirnares, Maila;Uliana, Livia C.;Vigh, Jozsef;von Gersdorff, Henrique;Prado, Marco A.;Guatimosim, Cristina
神经递质积聚到突触囊泡中的驱动力是由跨膜电化学梯度（ΔμH+）的产生提供的，该跨膜电化学梯度有两个组成部分：化学梯度（DpH，内部为酸性）和跨囊泡膜的电势（Δ μ H+，内部为正）。该梯度由产电液泡H+-ATP酶原位产生，其负责囊泡腔的酸化和正膜电位。在这里，我们调查的调制囊泡酸化通过使用酸性细胞器探针LysoTracker和pH敏感的探针LysoSensor在金鱼Mb型双极细胞终端。由于磷酸化可以调节神经内分泌细胞中分泌颗粒的酸化，我们研究了影响蛋白激酶的药物是否调节双极细胞末端的LysoTracker染色。我们发现，蛋白激酶C（PKC）激活诱导LysoTracker荧光增加。相比之下，蛋白激酶A（PKA）或钙/钙调蛋白激酶II（CaMKII）激活或抑制不改变LysoTracker荧光。使用pH依赖性荧光染料（LysoSensor），我们表明，PKC激活PMA诱导LysoSensor荧光增加，而无活性的类似物4 α-PMA不能引起相同的效果。PMA诱导的这种增加可被PKC抑制剂calphostin C和staurosporine阻断。这些结果表明，PKC的磷酸化可能会增加视网膜双极细胞中突触囊泡的酸化，因此有可能调节突触囊泡内的谷氨酸浓度。
The driving force for neurotransmitter accumulation into synaptic vesicles is provided by the generation of a transmembrane electrochemical gradient (ΔμH+) that has two components: a chemical gradient (DpH, inside acidic) and an electrical potential across the vesicular membrane (ΔΨ, inside positive). This gradient is generated in situ by the electrogenic vacuolar H+-ATPase, which is responsible for the acidification and positive membrane potential of the vesicle lumen. Here, we investigate the modulation of vesicle acidification by using the acidic-organelle probe LysoTracker and the pH-sensitive probe LysoSensor at goldfish Mb-type bipolar cell terminals. Since phosphorylation can modulate secretory granule acidification in neuroendocrine cells, we investigated if drugs that affect protein kinases modulate LysoTracker staining of bipolar cell terminals. We find that protein kinase C (PKC) activation induces an increase in LysoTracker-fluorescence. By contrast, protein kinase A (PKA) or calcium/calmodulin kinase II (CaMKII) activation or inhibition did not change LysoTracker-fluorescence. Using a pH-dependent fluorescent dye (LysoSensor) we show that the PKC activation with PMA induces an increase in LysoSensor-fluorescence, whereas the inactive analog 4alpha-PMA was unable to cause the same effect. This increase induced by PMA was blocked by PKC inhibitors, calphostin C and staurosporine. These results suggest that phosphorylation by PKC may increase synaptic vesicle acidification in retinal bipolar cells and therefore has the potential to modulate glutamate concentrations inside synaptic vesicles.
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影响因子：
16.2
作者：
Mennerick, S;Matthews, G
通讯作者：
Matthews, G
影响因子：
5.5
作者：
Minami, N;Berglund, K;Tachibana, M
通讯作者：
Tachibana, M
影响因子：
64.5
作者：
MAYFORD, M;WANG, J;ODELL, TJ
通讯作者：
ODELL, TJ
影响因子：
4.7
作者：
Camacho, M;Machado, JD;Borges, R
通讯作者：
Borges, R
影响因子：
5.3
作者：
Holt, M;Cooke, A;Lagnado, L
通讯作者：
Lagnado, L