Ohtsuka T, Ozawa M, Katayama T, Ishibashi S
Department of Physiological Chemistry, Hiroshima University School of Medicine, Japan.
Arch Biochem Biophys. 1988 May 1;262(2):416-21. doi: 10.1016/0003-9861(88)90392-x.
The phosphorylation of 46K protein(s), which was generally observed in parallel with an activation of NADPH oxidase of guinea pig polymorphonuclear leukocytes (PMNL) in our previous studies (N. Okamura et al. (1984) Arch. Biochem. Biophys. 228, 270-277; T. Ohtsuka et al. (1987) J. Biochem. 101, 897-903), was increased by treatment with 1-oleoyl-2-acetylglycerol (OAG), even at low concentrations at which both superoxide anion (O2-) production and arachidonate release were little induced. On the other hand, exposure of PMNL to low concentrations of a calcium ionophore, A23187, stimulated arachidonate release without causing substantial O2- production and increase in phosphorylation of 46K protein(s). Simultaneous addition of the above-mentioned suboptimal concentrations of both OAG and A23187 markedly enhanced O2- production in PMNL. This enhancing effect may be ascribable to the increase in the phosphorylation of 46K protein(s) and arachidonate release, which are induced by the addition of OAG and A23187, respectively. Another arachidonate-releasing agent, N-formyl-methionylleucyl-phenylalanine (FMLP), also stimulated O2- production in accordance with an increase in the arachidonate release and protein phosphorylation. Simultaneous addition of OAG significantly enhanced the FMLP-induced O2- production, presumably by maintaining the 46K protein phosphorylation which would facilitate the effect of arachidonate released by FMLP. Thus, the present results suggest that phosphorylation of 46K protein(s) and arachidonate release synergistically induce O2- production in PMNL, although either of them alone hardly induces the production.
在我们之前的研究中（N. 冈村等人，(1984)《生物化学与生物物理学报》228, 270 - 277；大冢彻等人，(1987)《生物化学杂志》101, 897 - 903），46K蛋白的磷酸化通常与豚鼠多形核白细胞（PMNL）的NADPH氧化酶激活同时出现。用1 - 油酰基 - 2 - 乙酰甘油（OAG）处理可增加其磷酸化，即使在低浓度下，超氧阴离子（O₂⁻）产生和花生四烯酸释放几乎未被诱导时也是如此。另一方面，将PMNL暴露于低浓度的钙离子载体A23187，可刺激花生四烯酸释放，但不会引起大量O₂⁻产生以及46K蛋白磷酸化增加。同时添加上述次优浓度的OAG和A23187可显著增强PMNL中的O₂⁻产生。这种增强作用可能归因于分别由OAG和A23187添加所诱导的46K蛋白磷酸化增加和花生四烯酸释放。另一种花生四烯酸释放剂N - 甲酰 - 甲硫氨酰 - 亮氨酰 - 苯丙氨酸（FMLP）也根据花生四烯酸释放和蛋白磷酸化的增加刺激O₂⁻产生。同时添加OAG可显著增强FMLP诱导的O₂⁻产生，推测是通过维持46K蛋白磷酸化，这将促进FMLP释放的花生四烯酸的作用。因此，目前的结果表明，46K蛋白的磷酸化和花生四烯酸释放协同诱导PMNL中的O₂⁻产生，尽管它们单独任何一个都几乎不诱导这种产生。
