Institute of Technology, University of Tartu, Tartu, Estonia.
Institute of Technology, University of Tartu, Tartu, Estonia.
Virology. 2023 Oct;587:109853. doi: 10.1016/j.virol.2023.109853. Epub 2023 Jul 26.
The genome of human papillomaviruses (HPVs) encodes the E1 replication factor, whose biological activities are regulated by cellular protein kinases. Here, the phosphorylation pattern of the E1 helicase of oncogenic mucosotropic HPV18 was investigated both in vitro and in vivo. Four serine residues located in a short peptide within a localization regulatory region were found to be phosphorylated in both experimental settings. We demonstrate that this peptide is targeted in vitro by various protein kinases, including CK2, PKA, and CKD2/cyclin A/B/E complexes. Through point mutagenesis, we show that phosphorylation of this region is essential for E1 subcellular localization, the interaction of E1 with the E2 protein, and replication of the HPV18 genome. Furthermore, we demonstrate the functional conservation of this phosphorylation across the E1 proteins of the low-risk mucosotropic HPV11 and high-risk cutaneotropic HPV5. These findings provide deeper insights into the phosphorylation-mediated regulation of biological activities of the E1 protein.
人乳头瘤病毒（HPV）的基因组编码 E1 复制因子，其生物学活性受细胞蛋白激酶调节。在此，我们研究了致癌黏膜型 HPV18 的 E1 解旋酶在体内和体外的磷酸化模式。在这两种实验条件下，均发现位于定位调节区的短肽中的四个丝氨酸残基被磷酸化。我们证明该肽在体外可被多种蛋白激酶靶向，包括 CK2、PKA 和 CKD2/周期蛋白 A/B/E 复合物。通过定点突变，我们表明该区域的磷酸化对于 E1 亚细胞定位、E1 与 E2 蛋白的相互作用以及 HPV18 基因组的复制至关重要。此外，我们还证明了这种磷酸化在低风险黏膜型 HPV11 和高风险皮肤型 HPV5 的 E1 蛋白中具有功能保守性。这些发现为 E1 蛋白的生物学活性的磷酸化介导调节提供了更深入的了解。
