Matsumoto T, Molski T F, Kanaho Y, Becker E L, Sha'afi R I
Biochem Biophys Res Commun. 1987 Mar 13;143(2):489-98. doi: 10.1016/0006-291x(87)91380-5.
The addition of the chemotactic factor fMet-Leu-Phe to cell homogenates causes a decrease in the pertussis toxin catalyzed ADP-ribosylation of a 41 kDa protein. The fMet-Leu-Phe induced decrease is not abolished in homogenates prepared from phorbol 12-myristate 13-acetate treated neutrophils. This decreased ribosylation probably reflects a dissociation of the GTP-binding protein oligomer that is not followed by association, possibly because of the release of the alpha-subunit into the suspending medium. Furthermore, fMet-Leu-Phe stimulates the binding of radiolabelled guanylylimidodiphosphate to membrane preparations. Again, the stimulated binding of guanylylimidodiphosphate is not affected by treating the intact neutrophils with phorbol 12-myristate 13-acetate. In addition leukotriene B4, platelet activating factor and fMet-Leu-Phe activate a high-affinity GTPase in membrane preparations. The basal level of this GTPase activity is dramatically inhibited in membrane preparations isolated from cells treated with phorbol 12-myristate 13-acetate. On the other hand, the fMet-Leu-Phe stimulated component is only marginally reduced. The present findings suggest that PMA does not prevent receptor G-protein interaction.
向细胞匀浆中添加趋化因子甲酰甲硫氨酸-亮氨酸-苯丙氨酸（fMet-Leu-Phe）会导致百日咳毒素催化的41 kDa蛋白的ADP核糖基化减少。在佛波酯12-肉豆蔻酸酯13-乙酸酯处理的中性粒细胞制备的匀浆中，fMet-Leu-Phe诱导的减少并未消除。这种核糖基化减少可能反映了GTP结合蛋白寡聚体的解离，且随后未发生缔合，可能是由于α亚基释放到悬浮介质中。此外，fMet-Leu-Phe刺激放射性标记的鸟苷酰亚胺二磷酸与膜制剂的结合。同样，鸟苷酰亚胺二磷酸的刺激结合不受佛波酯12-肉豆蔻酸酯13-乙酸酯处理完整中性粒细胞的影响。此外，白三烯B4、血小板活化因子和fMet-Leu-Phe可激活膜制剂中的高亲和力GTP酶。在用佛波酯12-肉豆蔻酸酯13-乙酸酯处理的细胞分离的膜制剂中，这种GTP酶活性的基础水平受到显著抑制。另一方面，fMet-Leu-Phe刺激的组分仅略有降低。目前的研究结果表明，佛波酯不会阻止受体与G蛋白的相互作用。
