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起着关键的调控作用。该结构域与结构化RNA结合并参与蛋白质-蛋白质相互作用。RNA依赖性蛋白激酶（PKR）和核因子90（NF 90）各自含有两个dsRBM。PKR是一种细胞蛋白激酶，由干扰素诱导，调节病毒感染和细胞生长控制中涉及的蛋白质合成和信号转导途径。因此，PKR受到严格调控，并从各种来源接收信号。NF 90的几种亚型存在于细胞中，包括 C-末端变体NF 110和该蛋白质家族的成员已被认为是PKR的调节剂和底物。NF 90家族蛋白在有丝分裂期间被严重磷酸化，并且已经在包括转录、翻译和RNA周转在内的几个水平上与基因表达的调节相关。NF 90纯化为具有核因子45（NF 45）的异二聚体，其也可以调节PKR和NF 90两者的功能。 本申请的总体目标是了解NF 90家族蛋白质的结构和功能，阐明NF 90/110、NF 45和PKR之间的功能关系，并探索NF 90家族蛋白质在病毒感染和正常细胞中的作用。为此，我们将使用当前的技术，包括质谱和RNA干扰，来检查以下内容： 1. NF 90/110和NF 45在人细胞和酵母模型系统中对PKR的调节。 2. NF 90/110通过PKR磷酸化和在有丝分裂中的作用。 3. NF 90亚型形成的蛋白复合物以及病毒感染、干扰素治疗和细胞周期阻滞所带来的变化。 4. NF 90亚型在腺病毒和HIV感染中的功能

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.