Guanylate cyclase and cyclic GMP-dependent protein kinase regulate agrin signaling at the developing neuromuscular junction
Guanylate cyclase and cyclic GMP-dependent protein kinase regulate agrin signaling at the developing neuromuscular junction
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DOI：
10.1016/j.ydbio.2007.04.021
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发表时间：
2007-07-15
影响因子：
2.7
通讯作者：
Browning, Darren D.
中科院分区：
文献类型：
--
作者：
Godfrey, Earl W.;Longacher, Matthew;Browning, Darren D.
在神经肌肉接头 (NMJ) 形成过程中，运动轴突分泌的集聚蛋白向胚胎肌细胞发出信号，以组织突触后装置，包括密集的乙酰胆碱受体 (AChR) 聚集体。胚胎 NMJ 的集聚蛋白信号传导需要一氧化氮合酶 (NOS) 的活性。 NOS 常见的下游效应器是合成环 GMP 的鸟苷酸环化酶 (GC) 和环 GMP 依赖性蛋白激酶 (PKG)。在这里，我们表明 GC 和 PKG 对于非洲爪蟾胚胎 NMJ 中的集聚蛋白信号传导非常重要。 GC 和 PKG 抑制剂均可将胚胎肌肉中的内源性 AChR 聚集减少 50-85%，并阻断培养的胚胎肌肉细胞中集聚蛋白诱导的 AChR 聚集。环状 GMP 类似物 8-溴-环状 GMP 可将胚胎肌肉中的内源性 AChR 聚集增加至对照水平的 3 至 4 倍。胚胎中GC或PKG的过度表达使AChR聚集面积增加了60-170%，而GC的显性失活形式的表达抑制了内源聚集50%。这些结果表明胚胎肌细胞中的集聚蛋白信号传导需要GC和PKG以及NOS的活性。 (c) 2007 Elsevier Inc. 保留所有权利。
During formation of the neuromuscular junction (NMJ), agrin secreted by motor axons signals the embryonic muscle cells to organize a postsynaptic apparatus including a dense aggregate of acetylcholine receptors (AChRs). Agrin signaling at the embryonic NMJ requires the activity of nitric oxide synthase (NOS). Common downstream effectors of NOS are guanylate cyclase (GC), which synthesizes cyclic GMP, and cyclic GMP-dependent protein kinase (PKG). Here we show that GC and PKG are important for agrin signaling at the embryonic NMJ of the frog, Xenopus laevis. Inhibitors of both GC and PKG reduced endogenous AChR aggregation in embryonic muscles by 50-85%, and blocked agrin-induced AChR aggregation in cultured embryonic muscle cells. A cyclic GMP analog, 8-bromo-cyclic GMP, increased endogenous AChR aggregation in embryonic muscles to 3- to 4-fold control levels. Overexpression of either GC or PKG in embryos increased AChR aggregate area by 60-170%, whereas expression of a dominant negative form of GC inhibited endogenous aggregation by 50%. These results indicate that agrin signaling in embryonic muscle cells requires the activity of GC and PKG as well as NOS. (c) 2007 Elsevier Inc. All rights reserved.