蛋白I是一种来自淋病奈瑟菌的可转运离子通道，它能选择性抑制人类中性粒细胞的胞吐作用，而不抑制超氧阴离子的产生。

Protein I, a translocatable ion channel from Neisseria gonorrhoeae, selectively inhibits exocytosis from human neutrophils without inhibiting O2- generation.

作者信息

Haines K A, Yeh L, Blake M S, Cristello P, Korchak H, Weissmann G

机构信息

Department of Medicine, New York University Medical Center, New York 10016.

出版信息

J Biol Chem. 1988 Jan 15;263(2):945-51.

PMID:2826469

Abstract

Protein I, the major outer membrane protein of Neisseria gonorrhoeae, is a voltage-dependent anion channel which can translocate from the gonococcus into human cells. Since granule exocytosis from neutrophils is regulated by ion fluxes, we examined the effect of protein I on neutrophil activation. Pretreatment with protein I (250 nM) impaired degranulation from neutrophils: beta-glucuronidase release decreased to 27 +/- 6% S.E. of cells treated with N-f-Met-Leu-Phe (fMLP, 0.1 microM) and to 13 +/- 4% of cells treated with leukotriene B4 (LTB4, 0.1 microM); lysozyme release decreased to 52 +/- 17% of fMLP-treated cells and 22 +/- 9% of LTB4-treated cells. Morphometric analysis was consistent: control neutrophils increased their surface membrane after fMLP (43.3 +/- 5.6 microns relative perimeter versus 71.4 +/- 3.7 microns) while protein I-treated neutrophils did not (29.4 +/- 2 (S.E.) microns relative perimeter versus 34 +/- 4 microns). Enzyme release after exposure to phorbol myristate acetate was not affected (lysozyme: 86 +/- 27% of control). Cell/cell aggregation in response to fMLP was inhibited by treatment with protein I. However, generation of O2 was not affected. Protein I altered the surface membrane potential (Oxonol V): protein I evoked a transient membrane hyperpolarization which was not inhibited by furosemide. After exposure to fMLP, protein I-treated neutrophils underwent a furosemide-sensitive hyperpolarization rather than the usual depolarization. Protein I did not alter increments in [Ca]i (Fura-2) stimulated by fMLP (460 +/- 99 nM (S.E.) versus 377 +/- 44 nM) nor decrements in [pH]i (7.22 +/- 0.04 S.E. versus 7.22 +/- 0.02, bis-(carboxy-ethyl)carboxyfluorescein). The results suggest that degranulation and O2 generation have separate ionic requirements and that protein I interrupts the activation sequence proximal to activation of protein kinase C.

摘要

蛋白I是淋病奈瑟菌的主要外膜蛋白，是一种电压依赖性阴离子通道，可从淋球菌转运至人体细胞。由于中性粒细胞的颗粒胞吐作用受离子通量调节，我们研究了蛋白I对中性粒细胞活化的影响。用蛋白I（250 nM）预处理会损害中性粒细胞的脱颗粒作用：β-葡萄糖醛酸酶释放量降至用N-甲酰甲硫氨酰亮氨酰苯丙氨酸（fMLP，0.1 microM）处理的细胞的27±6%标准误，以及用白三烯B4（LTB4，0.1 microM）处理的细胞的13±4%；溶菌酶释放量降至fMLP处理细胞的52±17%和LTB4处理细胞的22±9%。形态计量分析结果一致：对照中性粒细胞在fMLP刺激后其表面膜增加（相对周长43.3±5.6微米对71.4±3.7微米），而用蛋白I处理的中性粒细胞则没有（相对周长29.4±2（标准误）微米对34±4微米）。暴露于佛波酯肉豆蔻酸酯后酶的释放不受影响（溶菌酶：为对照的86±27%）。用蛋白I处理可抑制fMLP诱导的细胞/细胞聚集。然而，O2的产生不受影响。蛋白I改变了表面膜电位（氧化苯乙烯V）：蛋白I引起短暂的膜超极化，呋塞米不能抑制该超极化。暴露于fMLP后，用蛋白I处理的中性粒细胞经历了呋塞米敏感的超极化，而不是通常的去极化。蛋白I没有改变fMLP刺激引起的[Ca]i增加（460±99 nM（标准误）对377±44 nM），也没有改变[pH]i的降低（7.22±0.04标准误对7.22±0.02，双（羧乙基）羧基荧光素）。结果表明，脱颗粒作用和O2的产生有不同的离子需求，并且蛋白I中断了蛋白激酶C激活近端的激活序列。