Kato Masahiko, Yamaguchi Takafumi, Tachibana Atsushi, Kimura Hirokazu
Department of Allergy and Immunology, Gunma Children's Medical Center, Hokkitsu, Japan.
Int Arch Allergy Immunol. 2005;137 Suppl 1:27-34. doi: 10.1159/000085429. Epub 2005 Jun 2.
Protein kinase C (PKC) comprises a family of isoenzymes playing a key role in downstream signaling and cell functions. PKCs are grouped according to molecular structure and mode of activation: 'conventional' PKCs (alpha, betaI, betaII, gamma), 'novel' PKCs (delta, epsilon, mu, theta, eta), and 'atypical' PKCs (zeta, tau/lambda). Here we compared the influence of PKC zeta on the function of human eosinophils and neutrophils.
After pretreating the cells with a myristoylated specific PKC zeta inhibitor, a myristoylated PKC eta inhibitor, or bisindolylmaleimide I (Bis I; an inhibitor of conventional and novel PKCs), we examined N-formyl-methionyl-leucyl-phenylalanine (FMLP)- or 4-phorbol 12-myristate 13-acetate (PMA)-evoked superoxide anion (O(2)(-)) generation. Induced PKC translocation was characterized using confocal laser scanning microscopy.
The PKC zeta inhibitor significantly blocked FMLP- or PMA-induced O(2)(-) generation by eosinophils. However, this inhibitor attenuated PMA- but not FMLP-induced O(2)(-) generation by neutrophils. In contrast, Bis I inhibited FMLP-induced O(2)(-) generation by eosinophils and neutrophils in a similar manner. The PKC eta inhibitor had no significant effect, since both cell types lack PKC eta; this confirmed specificity of PKC zeta inhibitor effects. Finally, the translocation of PKC zeta to the plasma membrane induced by FMLP in both eosinophils and neutrophils was started at 1 min while the translocation was maintained for 15 min in eosinophils but not in neutrophils.
An atypical PKC, PKC zeta, regulates human eosinophil and neutrophil functions in a differential manner.
蛋白激酶C（PKC）是一组同工酶，在下游信号传导和细胞功能中起关键作用。PKC根据分子结构和激活方式进行分类：“传统”PKC（α、βI、βII、γ）、“新型”PKC（δ、ε、μ、θ、η）和“非典型”PKC（ζ、τ/λ）。在此，我们比较了PKCζ对人嗜酸性粒细胞和中性粒细胞功能的影响。
用肉豆蔻酰化的特异性PKCζ抑制剂、肉豆蔻酰化的PKCη抑制剂或双吲哚马来酰亚胺I（Bis I；传统和新型PKC的抑制剂）预处理细胞后，我们检测了N-甲酰甲硫氨酰亮氨酰苯丙氨酸（FMLP）或4-佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）诱导的超氧阴离子（O₂⁻）生成。使用共聚焦激光扫描显微镜对诱导的PKC易位进行表征。
PKCζ抑制剂显著阻断了嗜酸性粒细胞由FMLP或PMA诱导的O₂⁻生成。然而，该抑制剂减弱了中性粒细胞由PMA而非FMLP诱导的O₂⁻生成。相比之下，Bis I以类似方式抑制嗜酸性粒细胞和中性粒细胞由FMLP诱导的O₂⁻生成。PKCη抑制剂没有显著作用，因为两种细胞类型都缺乏PKCη；这证实了PKCζ抑制剂作用的特异性。最后，FMLP在嗜酸性粒细胞和中性粒细胞中诱导的PKCζ向质膜的易位在1分钟时开始，而在嗜酸性粒细胞中易位持续15分钟，在中性粒细胞中则不然。
一种非典型PKC，即PKCζ，以不同方式调节人嗜酸性粒细胞和中性粒细胞的功能。
