Otte A P, Kramer I M, Mannesse M, Lambrechts C, Durston A J
Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht.
Development. 1990 Oct;110(2):461-70. doi: 10.1242/dev.110.2.461.
Recently, we presented evidence that protein kinase C (PKC) is involved in mediating the endogenous signals that induced competent Xenopus ectoderm to differentiate to neural tissue. We report here that PKC is already strongly activated in neural-induced ectoderm from midgastrula embryos and that this activation runs parallel with an increase in the level of inositol phosphates. We further identify several proteins that are phosphorylated, both in natural neural-induced ectoderm and in TPA-treated ectoderm, suggesting that they are phosphorylated through the PKC route. We found no major changes in PKC activity among different pregastrula stages, including the unfertilized egg. However, PKC isolated from animal, ectodermal cells is highly sensitive to Ca2+ and can be activated by low concentrations, (6-25 microM) of arachidonic acid, while PKC isolated from vegetal, endodermal cells is more insensitive to Ca2+ and cannot be activated by arachidonic acid. These results suggest that different PKC isozymes are present in animal and vegetal cells.
最近，我们提供了证据表明蛋白激酶C（PKC）参与介导诱导非洲爪蟾感受态外胚层分化为神经组织的内源性信号。我们在此报告，PKC在原肠胚中期胚胎的神经诱导外胚层中已被强烈激活，且这种激活与肌醇磷酸水平的增加平行。我们进一步鉴定了几种在天然神经诱导外胚层和佛波酯（TPA）处理的外胚层中均被磷酸化的蛋白质，这表明它们是通过PKC途径被磷酸化的。我们发现，在不同的原肠胚前期阶段，包括未受精卵中，PKC活性没有重大变化。然而，从动物外胚层细胞分离的PKC对Ca2+高度敏感，并且可以被低浓度（6 - 25 microM）的花生四烯酸激活，而从植物内胚层细胞分离的PKC对Ca2+更不敏感，并且不能被花生四烯酸激活。这些结果表明，动物和植物细胞中存在不同的PKC同工酶。
