Yamaguchi M, Sasaki J, Kuwana M, Sakai M, Okamura N, Ishibashi S
Department of Physiological Chemistry, Hiroshima University School of Medicine, Japan.
Arch Biochem Biophys. 1993 Oct;306(1):209-14. doi: 10.1006/abbi.1993.1502.
Protein phosphatase inhibitors, okadaic acid and calyculin A, potentiated and elongated N-formyl-methionyl-leucyl-phenylalanine-induced superoxide anion (O2-) production in guinea pig neutrophils. The activity of NADPH oxidase in the membrane fraction prepared from phorbol 12-myristate 13-acetate-stimulated neutrophils was inactivated by the addition of the cytosol from resting neutrophils, such inactivation of NADPH oxidase was also suppressed by the protein phosphatase inhibitors. We previously reported that phosphorylation of the 46-kDa protein by protein kinase C is one of the activation mechanisms of NADPH oxidase-dependent superoxide anion production. In the cytosol fraction, we found protein phosphatase activity that catalyzed dephosphorylation of 32P-labeled phosphoproteins including the 46-kDa protein. Dephosphorylation of the 46-kDa protein was inhibited by the addition of okadaic acid and calyculin A. These results indicate that dephosphorylation of the 46-kDa protein by protein phosphatase is involved in the inactivation of NADPH oxidase. NADPH oxidase activity in guinea pig neutrophil may be regulated by the phosphorylation/dephosphorylation state of the 46-kDa protein by protein kinase C and protein phosphatase.
蛋白磷酸酶抑制剂冈田酸和花萼海绵诱癌素A增强并延长了豚鼠嗜中性粒细胞中N - 甲酰 - 甲硫氨酰 - 亮氨酰 - 苯丙氨酸诱导的超氧阴离子（O2-）生成。从佛波酯12 - 肉豆蔻酸酯13 - 乙酸盐刺激的嗜中性粒细胞制备的膜组分中，NADPH氧化酶的活性会因加入静息嗜中性粒细胞的胞质溶胶而失活，蛋白磷酸酶抑制剂也能抑制NADPH氧化酶的这种失活。我们之前报道过，蛋白激酶C使46 kDa蛋白磷酸化是NADPH氧化酶依赖性超氧阴离子生成的激活机制之一。在胞质溶胶组分中，我们发现了一种蛋白磷酸酶活性，它能催化包括46 kDa蛋白在内的32P标记的磷蛋白的去磷酸化。加入冈田酸和花萼海绵诱癌素A可抑制46 kDa蛋白的去磷酸化。这些结果表明，蛋白磷酸酶使46 kDa蛋白去磷酸化与NADPH氧化酶的失活有关。豚鼠嗜中性粒细胞中的NADPH氧化酶活性可能受蛋白激酶C和蛋白磷酸酶对46 kDa蛋白磷酸化/去磷酸化状态的调节。
