ANALYSIS OF THE POSTTRANSLATIONAL MODIFICATIONS OF THE INFLUENZA-VIRUS M(2) PROTEIN
ANALYSIS OF THE POSTTRANSLATIONAL MODIFICATIONS OF THE INFLUENZA-VIRUS M(2) PROTEIN
复制标题
DOI：
10.1128/jvi.69.2.1219-1225.1995
复制
发表时间：
1995-02-01
影响因子：
5.4
通讯作者：
LAMB, RA
中科院分区：
文献类型：
--
作者：
HOLSINGER, LJ;SHAUGHNESSY, MA;LAMB, RA
研究了甲型流感病毒M（2）蛋白的翻译后修饰位点，并分析了这些修饰对M（2）蛋白离子通道活性的影响。M（2）蛋白胞外域中的半胱氨酸残基17和19形成二硫键。胞质尾部通过棕榈酰化进行后修饰，诱变研究支持半胱氨酸残基50是脂肪酰化位点的观点。此外，发现M（2）蛋白质的胞质尾区通过在特定丝氨酸残基上添加磷酸进行后修饰。M（2）蛋白质尾区丝氨酸残基的定点突变，结合磷酸氨基酸分析，表明丝氨酸残基64是磷酸化的主要位点，但丝氨酸残基82，89和93也被磷酸化，但程度要低得多。在感染流感病毒的哺乳动物细胞中表达的M（2）蛋白，在从DNA表达载体表达M（2）蛋白的哺乳动物细胞中，以及当M（2）蛋白在非洲爪蟾卵母细胞中表达时，发生二硫键形成、棕榈酰化和磷酸化。表达野生型和位点特异性改变形式的M（2）蛋白的非洲爪蟾卵母细胞的膜电流，以消除翻译后修饰，表明没有翻译后修饰显着影响卵母细胞中M（2）蛋白的离子通道活性。因此，这些数据并不表明M（2）蛋白的翻译后修饰在其离子通道活性中的功能作用。
The sites of posttranslational modifications of the influenza A virus M(2) protein were examined, and the effect of these modifications on the M(2) protein ion channel activity was analyzed. Cysteine residues 17 and 19 in the M(2) protein ectodomain form disulfide bonds. The cytoplasmic tail is posttranslationally modified by palmitoylation, and mutagenic studies support the view that cystein residue 50 is the site for fatty acylation. In addition, the cytoplasmic tail of the M(2) protein was found to be posttranslationally modified by the addition of phosphate to specific serine residues. Site-directed mutagenesis of serine residues in the M(2) protein cytoplasmic tail, combined with phosphoamino acid analysis, indicated that serine residue 64 is the predominant site for phosphorylation but that serine residues 82, 89, and 93 were also phosphorylated but to much less extents. Disulfide-bond formation, palmitoylation, and phosphorylation occurred on M(2) protein expressed in mammalian cells infected with influenza virus, in mammalian cells in which the M(2) protein was expressed from DNA expression vectors, and when the M(2) protein was expessed in oocytes of Xenopus laevis. The memebrane currents of oocytes of Xenopus laevis expressing wild-type and site-specifically altered forms of the M(2) protein, to ablate posttranslational modifications, indicated that none of the posttranslational modifications significantly affected the ion channel activity of the M(2) protein in oocytes. Therefore, these data do not indicate a functional role for posttranslational modifications of the M(2) protein in its ion channel activity.