人源DTD蛋白激活人神经母细胞瘤细胞非选择性阳离子通道

h-DTD actives the nonselective cation channels in neuroblastoma SH-SY5Y cell line

目的探讨人源D-酪氨酰tRNA脱酰基酶(h-DTD)对人神经母细胞瘤细胞SH-SY5Y的非选择性阳离子通道通透性的影响。方法利用毛细管电泳法检测原核表达纯化的h-DTD的体外脱酰酶活性;用W estern b lot法分析h-DTD在各组织和细胞中的表达谱;用膜片钳技术检测SH-SY5Y细胞全细胞电位。结果h-DTD具有体外脱酰酶活性,并在脑组织中高表达。在h-DTD蛋白存在的情况下,游离的D-氨基酸及L谷-氨酸能激活谷氨酸敏感的非选择性阳离子通道,导致细胞膜通透性增加。结论在神经系统,h-DTD蛋白可能通过维持游离D-氨基酸的浓度来影响非选择性阳离子通道的功能。

Objective To explore the function of human D-Tyr-tRNATyr deacylase （h-DTD） It＇s influence on nonselective cation channels permeability of Na^＋ , K^＋ and Ca^2＋ in neuroblastoma SH-SYSY cell line. Methods The enzyme activity of h-DTD was analyzed with capillary electrophoresis; then the h-DTD protein expression level was examined in different tissues and cell lines with western blot. The membrane patch clamp technology was used to test the whole-cell potential change in SH-SY5Y cell line. Results h-DTD has deacylase activity in vitro, and this protein is widely expressed in different tissues. With a peak found in brain. The L-glutamic acid sensitive channel could be motivated by D-amino acid and L-glutamid acid only in the presence of h-DTD and with increased iron permeability. Conclusion h-DTD may affect the nonselective cation channels through the regulation of dissociative D-form amino acid concentration, so it may function as a regulator.