Regulation of energy metabolism in macrophages during hypoxia - Roles of fructose 2,6-bisphosphate and ribose 1,5-bisphosphate
Regulation of energy metabolism in macrophages during hypoxia - Roles of fructose 2,6-bisphosphate and ribose 1,5-bisphosphate
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DOI：
10.1074/jbc.m101396200
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发表时间：
2001-07-27
影响因子：
4.8
通讯作者：
Uyeda, K
中科院分区：
文献类型：
--
作者：
Kawaguchi, T;Veech, RL;Uyeda, K
巨噬细胞可以通过转换为无氧糖酵解来适应缺氧。在这项研究中，我们研究了（a）果糖2，6-二磷酸（Fru-2，6-P-2）和核糖1，5-二磷酸（RiB-1，5-P-2）的作用，磷酸果糖激酶的有效激活剂，（B）负责合成RiB-1，5-P-2的酶，和（c）在缺氧初始阶段H36.12 j巨噬细胞中这些酶的调节机制。在缺氧后1分钟内，糖酵解通过磷酸果糖激酶的激活而被激活。在同一时期，Fru-2，6-P-2下降了50%，并在复氧后完全恢复。观察到cAMP水平的类似变化。相反，Rib-1，5-P-2浓度在缺氧后30 s迅速增加至最大水平8.0 +/- 0.9 nmol/g细胞。因此，Rib-1，5-P-2是在缺氧初始阶段增加糖酵解速率的主要因素。此外，我们发现Rib-1，5-P-2是通过两个步骤合成的：核糖-磷酸焦磷酸激酶（5-磷酸核糖-1-焦磷酸合成酶; PRPP合成酶）反应（EC 2.7.6.1）催化该反应，Rib-5-P + ATP --> PRPP + AMP和一种新的酶，“PRPP焦磷酸酶”催化该反应，PRPP --> Rib-1，5-P-2 + P-i。PRPP合成酶和PRPP焦磷酸酶在缺氧30 s后被激活。用1-十八烷基-2-甲基-外消旋-甘油-3-磷酸胆碱和钙磷蛋白C预处理可抑制缺氧30 s后核糖PRPP合成酶和PRPP焦磷酸酶的激活以及Rib-1，5-P-2的增加和磷酸果糖激酶的激活。这些数据表明，上述酶的激活是由蛋白激酶C介导的，通过激活磷脂酰肌醇特异性磷脂酶C在缺氧期间的巨噬细胞。
Macrophages can adapt to the absence of oxygen by switching to anaerobic glycolysis. In this study, we investigated (a) the roles of fructose 2,6-bisphosphate (Fru-2,6-P-2) and ribose 1,5-bisphosphate (Rib-1,5-P-2), Potent activators of phosphofructokinase, (b) the enzymes responsible for the synthesis of Rib-1,5-P-2, and (c) the mechanisms of regulation of these enzymes in H36.12j macrophages during the initial phase of hypoxia. Within I min after initiating hypoxia, glycolysis was activated through activation of phosphofructokinase. Over the same period, Fru-2,6-P-2 decreased 50% and recovered completely upon reoxygenation. Similar changes in cAMP levels were observed. In contrast, the Rib-1,5-P-2 concentration rapidly increased to a maximum level of 8.0 +/- 0.9 nmol/g cell 30 s after hypoxia. Thus, Rib-1,5-P-2 was the major factor increasing the rate of glycolysis during the initial phase of hypoxia. Moreover, we found that Rib-1,5-P-2 was synthesized by two steps: the ribose-phosphate pyrophosphokinase (5-phosphoribosyl-1-pyrophosphate synthetase; PRPP synthetase) reaction (EC 2.7.6.1) catalyzing the reaction, Rib-5-P + ATP --> PRPP + AMP and a new enzyme, "PRPP pyrophosphatase" catalyzing the reaction, PRPP --> Rib-1,5-P-2 + P-i. Both PRPP synthetase and PRPP pyrophosphatase were significantly activated 30 s after hypoxia. Pretreatment with 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine and calphostin C prevented the activation of ribose PRPP synthetase and PRPP pyrophosphatase as well as increase in Rib-1,5-P-2 and activation of phosphofructokinase 30 s after hypoxia. These data suggest that the activation of the above enzymes was mediated by protein kinase C acting via activation of phosphatidylinositol specific phospholipase C in the macrophages during hypoxia.