Guanine nucleotides reduce the free calcium requirement for secretion of granule constituents from permeabilized human neutrophils.
Guanine nucleotides reduce the free calcium requirement for secretion of granule constituents from permeabilized human neutrophils.
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鸟嘌呤核苷酸降低了透化的人中性粒细胞分泌颗粒成分所需的游离钙。
DOI：
10.1016/0167-4889(86)90101-1
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Stoehr,SJ
中科院分区：
文献类型：
--
作者：
Smolen,JE;Stoehr,SJ
人嗜中性粒细胞可以用胆固醇络合剂毛地黄皂苷透化，然后通过单独增加游离Ca 2+诱导分泌溶酶体成分。随着对Ca ~（2+）需求量的增加，维生素B-12结合蛋白、溶菌酶和β-葡萄糖醛酸酶依次释放。研究了各种鸟嘌呤核苷酸调节这种反应的能力。沿着GTP及其类似物5′-鸟苷酰亚氨基二磷酸（Gpp[NH]p）和鸟苷-5 ′-O-[3-硫代]-三磷酸（GTP[γS]）使所有三种颗粒成分分泌所需的Ca 2+减少三分之一至一个数量级。这种协同作用取决于所用鸟嘌呤核苷酸的浓度。Gpp[NH]p的作用可被无活性的衍生物GDP[β-S]阻断。具有活性的鸟嘌呤核苷酸，特别是GTP，本身就是刺激物。在高浓度的Ca 2+和GTP下，脱粒被显著抑制;高浓度的鸟苷酰[β，γ-亚甲基]二磷酸（Gpp[CH 2]p）也能抑制脱粒。GDP和GMP均无任何影响。当用百日咳毒素预处理中性粒细胞时，由fMet-Leu-Phe诱导的颗粒放电几乎完全被阻断，如其他人所报道的。如果用百日咳毒素预处理的中性粒细胞然后用毛地黄皂苷透化，则保持Ca 2+和刺激性鸟嘌呤核苷酸之间的协同作用。这些数据表明G蛋白参与由Ca 2+诱导的分泌;然而，该响应使用与由fMet-Leu-Phe触发的那些响应不同的G蛋白或不同的G蛋白库。
Human neutrophils can be permeabilized with the cholesterol complexing agent digitonin and then induced to secrete lysosomal constituents by increases in free Ca2+alone. In order of increasing requirements for Ca2+, vitamin B-12 binding protein, lysozyme and β-glucuronidase were released. A variety of guanine nucleotides were examined with respect to their abilities to modulate this response. GTP, along with its analogues 5′-guanylylimidodiphosphate (Gpp[NH]p) and guanosine-5′-O-[3-thio]-triphosphate (GTP[γS]) decreased the Ca2+requirements for secretion of all three granule constituents by one third to one order of magnitude. This synergy was dependent upon the concentration of guanine nucleotides employed. The effects of Gpp[NH]p could be blocked with the inactive derivative GDP[β-S]. The active guanine nucleotides, particularly GTP, served as stimuli in their own right. At high concentrations of Ca2+and GTP, degranulation was strikingly inhibited; inhibition was also achieved with high concentrations of guanylyl[β,γ-methylene]diphosphate (Gpp[CH2]p). Both GDP and GMP were without any effect. When neutrophils were pretreated with pertussis toxin, granule discharge induced by fMet-Leu-Phe was almost completely blocked, as reported by others. If the neutrophils pretreated with pertussis toxin were then permeabilized with digitonin, the synergy between Ca2+and the stimulatory guanine nucleotides was maintained. These data suggest the involvement of G-proteins in secretion induced by Ca2+; however, this response either uses a different G-protein or a different pool of G-proteins from those responses triggered by fMet-Leu-Phe.