PHOSPHORYLATION OF SER(232) DIRECTLY REGULATES THE TRANSCRIPTIONAL ACTIVITY OF THE P-PROTEIN OF HUMAN RESPIRATORY SYNCYTIAL VIRUS - PHOSPHORYLATION OF SER(237) MAY PLAY AN ACCESSORY ROLE
PHOSPHORYLATION OF SER(232) DIRECTLY REGULATES THE TRANSCRIPTIONAL ACTIVITY OF THE P-PROTEIN OF HUMAN RESPIRATORY SYNCYTIAL VIRUS - PHOSPHORYLATION OF SER(237) MAY PLAY AN ACCESSORY ROLE
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DOI：
10.1006/viro.1995.0013
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发表时间：
1995-11-10
期刊：
影响因子：
3.7
通讯作者：
DUPUY, LC
中科院分区：
文献类型：
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作者：
BARIK, S;MCLEAN, T;DUPUY, LC
人呼吸道合胞病毒（RSV）磷蛋白P在真核细胞中以磷酸化形式表达。重组蛋白的定点突变确定Ser（232）为体内磷酸化的主要位点。纯化的酪蛋白激酶II（CKII）在体外磷酸化细菌P蛋白导致Ser（237）的磷酸化，而主要是Ser（232）被粗细胞提取物磷酸化。细胞提取物中的P激酶活性表现出CKII的特性。虽然Ser（232，237）到Ala的双突变体几乎完全缺乏磷酸化和转录，但通过使用适当的P突变体或激酶，Ser（232）的磷酸化激活了P蛋白。Ser（237）的磷酸化仅在促进Ser（232）的磷酸化的程度上恢复活性。在RSV感染的细胞中的P蛋白的磷酸基团是高度稳定的，蛋白丝氨酸磷酸酶的抑制剂对磷酸盐的细胞内营业额没有影响。高度纯化的病毒聚合酶L具有转录活性，但缺乏P蛋白激酶活性。因此，CKII介导的Ser（232）磷酸化似乎是P蛋白活性的主要调节因子，而Ser（237）磷酸化在某些条件下可能参与调节作用。(C)1995学术出版社，Inc.
The phosphoprotein P of human respiratory syncytial virus (RSV) was expressed in eukaryotic cells in phosphorylated form. Site-directed mutagenesis of the recombinant protein established Ser(232) as the major site of phosphorylation in vivo. Phosphorylation of bacterially made P protein in vitro by purified casein kinase II (CKII) resulted in the phosphorylation of Ser(237), whereas mainly Ser(232) was phosphorylated by a crude cell extract. The P kinase activity in the cell extract exhibited properties characteristic of CKII. While the Ser(232,237) to Ala double mutant was nearly completely defective for phosphorylation and transcription, phosphorylation at Ser(232), through the use of appropriate P mutant or kinase, activated P protein. Phosphorylation of Ser(237) restored activity only to the extent it facilitated phosphorylation of Ser(232). Phosphate groups of P protein in RSV-infected cells were highly stable; inhibitors of protein serine phosphatases had no effect on the intracellular turnover of the phosphates. Highly purified viral polymerase L was transcriptionally active but devoid of P protein kinase activity. Thus, CKII-mediated phosphorylation of Ser(232) appears to be the primary regulator of P protein activity while phosphorylation of Ser(237) may be involved in a modulatory role under certain conditions. (C) 1995 academic Press, Inc.