Functions of Double-stranded RNA Binding Proteins

含有双链RNA结合基序(DsRBM)的蛋白质在原核生物和真核生物中都发挥着关键的调节作用。这个结构域与结构化RNA结合，并参与蛋白质之间的相互作用。RNA依赖蛋白激酶(PKR)和核因子90(NF90)各含有两个dsRBM。PKR是一种由干扰素诱导的细胞蛋白激酶，调节病毒感染和细胞生长控制中的蛋白质合成和信号转导途径。因此，PKR受到严格监管，并从各种来源接收信号。NF90的几种亚型存在于细胞中，包括 C末端突变体NF110及其家族成员被认为是PKR的调节因子和底物。NF90家族蛋白在有丝分裂过程中高度磷酸化，并在转录、翻译和RNA周转等多个水平上参与基因表达的调节。NF90是一种含有核因子45(NF45)的异源二聚体，它也可以调节PKR和NF90的功能。 本应用的总体目标是了解NF90家族蛋白的结构和功能，阐明NF90/110、NF45和PKR之间的功能关系，并探讨NF90家族蛋白在病毒感染和正常细胞中的作用(S)。为此，我们将利用目前的技术，包括质谱学和RNA干扰，来研究以下内容： 1.NF90/110和NF45对人细胞和酵母模型体系中PKR的调节 2.PKR对NF90/110的磷酸化及其在有丝分裂中的作用 3.NF90亚型形成的蛋白质复合体以及病毒感染、干扰素治疗和细胞周期阻断带来的变化。 4.NF90亚型在腺病毒和HIV感染中的作用。

Proteins containing the double-stranded RNA binding motif (dsRBM) play key regulatory roles in both prokaryotic and eukaryotic organisms. This domain binds to structured RNAs and participates in protein-protein interactions. The RNA-dependent protein kinase (PKR) and nuclear factor 90 (NF90) each contain two dsRBMs. PKR is a cellular protein kinase that is induced by interferon and regulates protein synthesis and signal transduction pathways involved in viral infection and cellular growth control. Accordingly, PKR is tightly regulated and receives signals from a variety of sources. Several isoforms of NF90 exist in cells, including the C-terminal variant NF110, and members of this protein family have been implicated as both regulators and substrates of PKR. The NF90 family proteins are heavily phosphorylated during mitosis and have been associated with the regulation of gene expression at several levels including transcription, translation, and RNA turnover. NF90 purifies as a heterodimer with nuclear factor 45 (NF45), which can also modulate the functions of both PKR and NF90. The overall objectives of this application are to develop an understanding of the structure and function of proteins in the NF90 family, to elucidate the functional relationships between NF90/110, NF45 and PKR, and to explore the role(s) of NF90 family proteins in virus-infected and normal cells. To these ends, we will use current technologies including mass spectrometry and RNA interference, to examine the following: 1. The regulation of PKR by NF90/110 and NF45 in human cells and the yeast model system. 2. The role of NF90/110 phosphorylation by PKR and in mitosis. 3. Protein complexes formed by NF90 isoforms and the changes brought about by viral infection, interferon treatment, and cell cycle block. 4. The functions of NF90 isoforms during infection with adenovirus and HIV.