Division of Medical Biotechnology, Paul-Ehrlich-Institut, Langen, Germany.
Clinic for Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany.
J Gen Virol. 2012 Nov;93(Pt 11):2425-2430. doi: 10.1099/vir.0.043273-0. Epub 2012 Aug 15.
The human immunodeficiency virus type 1 accessory protein Vif is important for viral infectivity because it counteracts the antiviral protein APOBEC3G (A3G). ³²P metabolic labelling of stimulated cells revealed in vivo phosphorylation of the control protein, whereas no serine/threonine phosphorylation was detected for Vif or the A3G protein. These data were confirmed by in vitro kinase assays using active recombinant kinase. Mitogen-activated protein kinase/extracellular signal-regulated kinase 2 efficiently phosphorylated its target ELK, but failed to phosphorylate Vif. Putative serine/threonine phosphorylation point mutations in Vif (T96, S144, S165, T188) using single-round infection assays demonstrated that these mutations did not alter Vif activity, with the exception of Vif.T96E. Interestingly, T96E and not T96A was functionally impaired, indicating that this residue is critical for Vif-A3G physical interaction and activity. Our data suggest that Vif and A3G are not serine/threonine phosphorylated in human cells and phosphorylation is not linked to their functional activities.
人类免疫缺陷病毒 1 型辅助蛋白 Vif 对于病毒感染性很重要，因为它可以对抗抗病毒蛋白 APOBEC3G（A3G）。³²P 代谢标记刺激细胞表明，对照蛋白发生体内磷酸化，而 Vif 或 A3G 蛋白未检测到丝氨酸/苏氨酸磷酸化。这些数据通过使用活性重组激酶的体外激酶测定得到证实。有丝分裂原激活的蛋白激酶/细胞外信号调节激酶 2 有效地磷酸化其靶蛋白 ELK，但未能磷酸化 Vif。使用单轮感染测定对 Vif（T96、S144、S165、T188）中的假定丝氨酸/苏氨酸磷酸化点突变表明，除了 Vif.T96E 之外，这些突变没有改变 Vif 活性。有趣的是，T96E 而不是 T96A 的功能受损，表明该残基对于 Vif-A3G 物理相互作用和活性至关重要。我们的数据表明，人类细胞中的 Vif 和 A3G 未发生丝氨酸/苏氨酸磷酸化，磷酸化与它们的功能活性无关。
