dos Passos J B, Vanhalewyn M, Brandão R L, Castro I M, Nicoli J R, Thevelein J M
Laboratorium voor Moleculaire Celbiologie, Katholieke Universiteit, Leuven, Belgium.
Biochim Biophys Acta. 1992 Jul 22;1136(1):57-67. doi: 10.1016/0167-4889(92)90085-p.
Addition of glucose-related fermentable sugars or protonophores to derepressed cells of the yeast Saccharomyces cerevisiae causes a 3- to 4-fold activation of the plasma membrane H(+)-ATPase within a few minutes. These conditions are known to cause rapid increases in the cAMP level. In yeast strains carrying temperature-sensitive mutations in genes required for cAMP synthesis, incubation at the restrictive temperature reduced the extent of H(+)-ATPase activation. Incubation of non-temperature-sensitive strains, however, at such temperatures also caused reduction of H(+)-ATPase activation. Yeast strains which are specifically deficient in the glucose-induced cAMP increase (and not in basal cAMP synthesis) still showed plasma membrane H(+)-ATPase activation. Yeast mutants with widely divergent activity levels of cAMP-dependent protein kinase displayed very similar levels of activation of the plasma membrane H(+)-ATPase. This was also true for a yeast mutant carrying a deletion in the CDC25 gene. These results show that the cAMP-protein kinase A signaling pathway is not required for glucose activation of the H(+)-ATPase. They also contradict the specific requirement of the CDC25 gene product. Experiments with yeast strains carrying point or deletion mutations in the genes coding for the sugar phosphorylating enzymes hexokinase PI and PII and glucokinase showed that activation of the H(+)-ATPase with glucose or fructose was completely dependent on the presence of a kinase able to phosphorylate the sugar. These and other data concerning the role of initial sugar metabolism in triggering activation are consistent with the idea that the glucose-induced activation pathways of cAMP-synthesis and H(+)-ATPase have a common initiation point.
向酿酒酵母（Saccharomyces cerevisiae）去阻遏细胞中添加与葡萄糖相关的可发酵糖或质子载体，会在几分钟内使质膜H⁺-ATP酶激活3至4倍。已知这些条件会导致cAMP水平迅速升高。在cAMP合成所需基因中携带温度敏感突变的酵母菌株中，在限制温度下孵育会降低H⁺-ATP酶的激活程度。然而，将非温度敏感菌株在这样的温度下孵育也会导致H⁺-ATP酶激活程度降低。在葡萄糖诱导的cAMP增加方面存在特异性缺陷（但基础cAMP合成无缺陷）的酵母菌株仍表现出质膜H⁺-ATP酶激活。cAMP依赖性蛋白激酶活性水平差异很大的酵母突变体，其质膜H⁺-ATP酶的激活水平非常相似。携带CDC25基因缺失的酵母突变体也是如此。这些结果表明，cAMP-蛋白激酶A信号通路对于葡萄糖激活H⁺-ATP酶并非必需。它们也与CDC25基因产物的特定需求相矛盾。对编码糖磷酸化酶己糖激酶PI和PII以及葡萄糖激酶的基因进行点突变或缺失突变后的酵母菌株实验表明，用葡萄糖或果糖激活H⁺-ATP酶完全依赖于能够磷酸化该糖的激酶存在。这些以及其他关于初始糖代谢在触发激活中作用的数据与以下观点一致，即葡萄糖诱导的cAMP合成和H⁺-ATP酶激活途径有一个共同的起始点。
