GABA(B) receptors couple to Gαq to mediate increases in voltage-dependent calcium current during development.
GABA(B) receptors couple to Gαq to mediate increases in voltage-dependent calcium current during development.
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DOI：
10.1111/jnc.13259
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发表时间：
2015-10
影响因子：
4.7
通讯作者：
Mynlieff M
中科院分区：
文献类型：
--
作者：
Karls A;Mynlieff M
已知代谢性GABAB受体可调节电压依赖性钙通道的活性。在此之前，我们已经证明GAAB受体偶联到一个非Gi/o G蛋白上，通过激活蛋白激酶C来促进新生大鼠海马神经元通过L型钙通道的钙内流。在本研究中，我们进一步研究了该信号通路的组成成分。在检测GABAB介导的钙内流增强作用之前，用吗啉寡核苷酸抑制G-αQ。当用吗啉介导的基因敲除G-αQ-G蛋白时，GABA受体激动剂巴氯芬(10μM)对钙电流或内流的增强作用被消除。这些数据表明，GABAB受体与GαQ偶联，调节钙内流。共聚焦成像分析说明GAAB受体与GαQ共定位，支持这一假说。此外，巴氯芬可引起蛋白激酶Cα(Protein Kinase Cα)的易位，但不影响蛋白激酶Cβ或蛋白激酶Cε，提示可能是蛋白激酶C的α亚型介导了钙电流增强。抑制钙/钙调蛋白依赖性激酶II(CaMKII)不影响巴氯芬介导的钙水平升高。总之，在发育过程中，GABAB受体的激活通过GαQ信号和PKCα的激活导致神经元亚群中钙离子的增加，而不涉及CaMKII。新生大鼠海马区GABAB受体的激活增强电压依赖性钙电流，而不依赖于Gi/o。在本研究中，用吗啉寡核苷酸敲除GαQ可消除钙内流的增强，蛋白激酶Cα可被GABAB受体激活。因此，我们推测GAAB受体与GQ偶联，激活PKCα，导致L型钙电流增强。
Metabotropic GABAB receptors are known to modulate the activity of voltage-dependent calcium channels. Previously, we have shown that GABAB receptors couple to a non-Gi/o G-protein to enhance calcium influx through L-type calcium channels by activating-protein kinase C in neonatal rat hippocampal neurons. In the current study, the components of this signaling pathway were investigated further. Gαq was knocked down using morpholino oligonucleotides prior to examining GABAB-mediated enhancement of calcium influx. When Gαq G-proteins were eliminated using morpholino-mediated knockdown, the enhancing effects of the GABAB receptor agonist baclofen (10 μM) on calcium current or entry were eliminated. These data suggest that GABAB receptors couple to Gαq to regulate calcium influx. Confocal imaging analysis illustrating colocalization of GABAB receptors with Gαq supports this hypothesis. Furthermore, baclofen treatment caused translocation of PKCα (protein kinase C α) but not PKCβ or PKCε, suggesting that it is the α isoform of PKC that mediates calcium current enhancement. Inhibition of calcium/calmodulin-dependent kinase II (CaMKII) did not affect the baclofen mediated enhancement of calcium levels. In summary, activation of GABAB receptors during development leads to increased calcium in a subset of neurons through Gαq signaling and PKCα activation without the involvement of CaMKII. Activation of GABAB receptors in the neonatal rat hippocampus enhance voltage dependent calcium currents independently of Gi/o. In the present study, knockdown of Gαq with morpholino oligonucleotides abolished enhancement of calcium influx and protein kinase Cα was activated by GABAB receptors. Therefore, we hypothesize that GABAB receptors couple to Gq to activate PKCα leading to enhancement of L-type calcium current.
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影响因子：
46.9
作者：
Judge, AD;Sood, V;MacLachlan, I
通讯作者：
MacLachlan, I
CAMKII将Ca2+通道的camkii tethers建立，建立了Ca2+信号的本地和专用集成商进行便利。
影响因子：
7.8
作者：
Hudmon, A;Schulman, H;Kim, J;Maltez, JM;Tsien, RW;Pitt, GS
通讯作者：
Pitt, GS
影响因子：
3
作者：
Bray, Jennifer G.;Mynlieff, Michelle
通讯作者：
Mynlieff, Michelle
影响因子：
4.7
作者：
Franek, M;Pagano, A;Blahos, J
通讯作者：
Blahos, J
影响因子：
3.3
作者：
Bray, J. G.;Mynlieff, M.
通讯作者：
Mynlieff, M.