Developmentally regulated changes in 1,2-diacylglycerol in Dictyostelium. Regulation by light and G proteins.
Developmentally regulated changes in 1,2-diacylglycerol in Dictyostelium. Regulation by light and G proteins.
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盘基网柄菌中 1,2-二酰基甘油的发育调节变化。
DOI：
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发表时间：
1993
影响因子：
4.8
通讯作者：
R. Firtel
中科院分区：
文献类型：
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作者：
A. B. Cubitt;S. Dharmawardhane;R. Firtel
我们已经测量了1，2-二酰基甘油（DG）的质量在Dictyosteoporosis的发展。DG水平最初在营养细胞中很高，在饥饿时降低，在聚集过程中增加，并在高潮期间急剧上升，伴随着SpiA（孢子细胞特异性基因）表达。这些结果是一致的DG参与高潮阶段的形态变化和细胞类型分化。突变体分析表明，聚集过程中DG的上升需要cAMP信号通路，但不是通过这些过程直接调节，而是通过cAMP诱导的发育程序。聚集过程中DG的积累比肌醇脂质水解预期的高约8倍（1），表明DG是由磷脂酰肌醇4，5-二磷酸以外的来源产生的。我们的数据表明，在聚集过程中，虽然有些DG是通过磷脂酶D活性形成的，但其他途径（如从头合成）可能是DG积累的更重要的调节因子。在生长高峰期，DG的积累与磷脂酸和磷脂酰乙醇的形成相关，表明磷脂酶D的激活。在此期间，许多磷脂的[3 H]棕榈酸酯标记迅速下降，表明此时磷脂的快速代谢。在黑暗中开发的蛞蝓暴露于光，启动高潮，导致快速DG积累，这表明磷脂水解的激活。DG积累的时间模式和水平在G α 1无效和过表达菌株中改变，表明G α 1在DG形成的上游。这些结果表明，特定途径的DG形成发育控制，并建议光，激活DG生产，诱导顶点之间可能存在联系。
We have measured 1,2-diacylglycerol (DG) mass during Dictyostelium development. DG levels are initially high in vegetative cells, decrease upon starvation, increase during aggregation, and rise dramatically during culmination, concomitant with SpiA (a spore cell-specific gene) expression. These results are consistent with DG being involved in culmination-stage morphological changes and cell-type differentiation. Mutant analysis shows that the rise in DG during aggregation requires cAMP signaling pathways but is not directly regulated through these processes but via developmental programs induced through cAMP. DG accumulation during aggregation is approximately 8-fold higher than would be expected from inositol lipid hydrolysis (1), suggesting that DG is produced from sources in addition to phosphatidylinositol 4,5-bisphosphate. Our data suggest that during aggregation, although some DG is formed through phospholipase D activity, other pathways (e.g. de novo synthesis) may be more important regulators of DG accumulation. During culmination, DG accumulation correlated with the formation of phosphatidic acid and phosphatidylethanol suggesting the activation of phospholipase D. During this time, the [3H]palmitate labeling of a number of phospholipids decreased rapidly, suggesting a rapid metabolism of phospholipids at this time. Exposure of slugs developed in the dark to light, which initiates culmination, causes rapid DG accumulation, suggesting the activation of phospholipid hydrolysis. The temporal pattern and level of DG accumulation is altered in G alpha 1 null and overexpressing strains, suggesting that G alpha 1 is upstream from DG formation during culmination. These results demonstrate that specific pathways of DG formation are under developmental control and suggest a possible link between light, the activation of DG production, and induction of culmination.