Okumura N, Miyatake Y, Takao T, Tamaru T, Nagai K, Okada M, Nakagawa H
Division of Metabolism, Osaka University.
J Biochem. 1994 Feb;115(2):304-8. doi: 10.1093/oxfordjournals.jbchem.a124333.
Vasoactive intestinal peptide (VIP), a neuropeptide coupled with adenylate cyclase, was found to induce neurite extension of PC12h cells. Neurites appeared within 1 h after addition of VIP and extended for at least 24 h. The half-maximal concentration for the effect of VIP was 50 nM. In addition to the morphological change, VIP induced expression of VGF protein, a neuron-specific protein associated with neuronal differentiation. Western blotting with anti-phosphotyrosine antibody showed that VIP stimulated tyrosine phosphorylation of two proteins of 42 and 44 kDa, which may be two isoforms of MAP kinase, erk1 and erk2. Activation of MAP kinases was confirmed by ion-exchange chromatography on a Mono Q column, from which VIP-induced kinase activity was co-eluted with MAP kinase-immunoreactivity. Tyrosine-phosphorylation of MAP kinases was also stimulated by forskolin or dibutyryl cAMP, indicating that activation of MAP kinases by VIP might be mediated by cAMP. These results suggest that VIP-induced differentiation of PC12 cells is associated with cAMP-dependent activation of MAP kinases.
血管活性肠肽（VIP）是一种与腺苷酸环化酶偶联的神经肽，已发现它能诱导PC12h细胞的神经突延伸。加入VIP后1小时内神经突出现，并至少延伸24小时。VIP产生效应的半数最大浓度为50 nM。除形态学变化外，VIP还诱导了VGF蛋白的表达，VGF蛋白是一种与神经元分化相关的神经元特异性蛋白。用抗磷酸酪氨酸抗体进行的蛋白质印迹分析表明，VIP刺激了42 kDa和44 kDa两种蛋白的酪氨酸磷酸化，这两种蛋白可能是丝裂原活化蛋白激酶（MAP激酶）的两种同工型，即erk1和erk2。通过在Mono Q柱上进行离子交换色谱法证实了MAP激酶的激活，VIP诱导的激酶活性与MAP激酶免疫反应性从该柱上共同洗脱下来。福斯可林或二丁酰环磷腺苷也刺激了MAP激酶的酪氨酸磷酸化，这表明VIP对MAP激酶的激活可能是由环磷腺苷介导的。这些结果表明，VIP诱导的PC12细胞分化与cAMP依赖性的MAP激酶激活有关。
