Ca2+ influx through L-type Ca2+ channels and Ca2+-induced Ca2+ release regulate cAMP accumulation and Epac1-dependent ERK 1/2 activation in INS-1 cells.
Ca2+ influx through L-type Ca2+ channels and Ca2+-induced Ca2+ release regulate cAMP accumulation and Epac1-dependent ERK 1/2 activation in INS-1 cells.
复制标题
Ca2 通过 L 型 Ca2 通道流入和 Ca2 诱导的 Ca2 释放调节 INS-1 细胞中 cAMP 积累和 Epac1 依赖性 ERK 1/2 激活。
DOI：
10.1016/j.mce.2015.09.034
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发表时间：
2016
影响因子：
4.1
通讯作者：
Hockerman,GregoryH
中科院分区：
文献类型：
--
作者：
Pratt,EvanPS;Salyer,AmyE;Guerra,MarcyL;Hockerman,GregoryH
我们先前报道了表达L型钙通道Cav1.2的细胞内II-III环的INS-1细胞（Cav1.2/II-III细胞）缺乏钙诱导的钙释放（CICR）。在这里，我们表明，葡萄糖刺激的ERK 1/2磷酸化（GSEP）是减缓和减少Cav1.2/II-III细胞相比，INS-1细胞。这与Cav1.2/II-III细胞中葡萄糖刺激的cAMP积累（GS-cAMP）减少平行。通过L-型Ca ~（2+）通道的Ca ~（2+）内流和CICR在INS-1细胞的GSEP和GS-cAMP中起作用，因为这两者都被尼卡地平或兰尼定抑制。此外，Epac 1选择性抑制剂CE 3F 4消除INS-1细胞中葡萄糖刺激的ERK激活，如使用基于FRET的传感器EKAR所测量的。非选择性Epac拮抗剂ESI-09抑制INS-1和Cav1.2/II-III细胞中的GSEP，但Epac 2选择性拮抗剂ESI-05和PKA拮抗剂Rp-cAMPs均不抑制。我们的结论是，L-型钙通道依赖的cAMP积累，这是由CICR放大，激活Epac 1和驱动GSEP在INS-1细胞。
We previously reported that INS-1 cells expressing the intracellular II-III loop of the L-type Ca2+channel Cav1.2 (Cav1.2/II-III cells) are deficient in Ca2+-induced Ca2+release (CICR). Here we show that glucose-stimulated ERK 1/2 phosphorylation (GSEP) is slowed and reduced in Cav1.2/II-III cells compared to INS-1 cells. This parallels a decrease in glucose-stimulated cAMP accumulation (GS-cAMP) in Cav1.2/II-III cells. Influx of Ca2+via L-type Ca2+channels and CICR play roles in both GSEP and GS-cAMP in INS-1 cells since both are inhibited by nicardipine or ryanodine. Further, the Epac1-selective inhibitor CE3F4 abolishes glucose-stimulated ERK activation in INS-1 cells, as measured using the FRET-based sensor EKAR. The non-selective Epac antagonist ESI-09 but not the Epac2-selective antagonist ESI-05 nor the PKA antagonist Rp-cAMPs inhibits GSEP in both INS-1 and Cav1.2/II-III cells. We conclude that L-type Ca2+channel-dependent cAMP accumulation, that's amplified by CICR, activates Epac1 and drives GSEP in INS-1 cells.