Edson Amanda J, Jacobsen Rhîan G, Lewis Aurélia E
Department of Biological Sciences, University of Bergen, Bergen, Vestland, Norway.
MicroPubl Biol. 2023 Mar 24;2023. doi: 10.17912/micropub.biology.000761. eCollection 2023.
Polyphosphoinositides (PPIn) play essential functions as lipid signalling molecules and many of their functions have been elucidated in the cytoplasm. However, PPIn are also intranuclear where they contribute to chromatin remodelling, transcription and mRNA splicing. Using quantitative interactomics, we have previously identified PPIn-interacting proteins with roles in RNA processing/splicing including the heterogeneous nuclear ribonucleoprotein U (hnRNPU/SAF-A). In this study, hnRNPU was validated as a direct PPIn-interacting protein via 2 regions located in the N and C termini. Furthermore, deletion of the polybasic motif region located at aa 9-24 in its DNA binding SAP domain prevented PPIn interaction. In conclusion, these results are consistent with hnRNPU harbouring a polybasic region with dual functions in DNA and PPIn interaction.
多磷酸肌醇（PPIn）作为脂质信号分子发挥着重要功能，其许多功能已在细胞质中得到阐明。然而，PPIn也存在于细胞核内，在那里它们参与染色质重塑、转录和mRNA剪接。我们之前利用定量相互作用组学鉴定了与PPIn相互作用的蛋白质，这些蛋白质在RNA加工/剪接中发挥作用，包括不均一核核糖核蛋白U（hnRNPU/SAF-A）。在本研究中，通过位于N端和C端的2个区域，hnRNPU被验证为直接与PPIn相互作用的蛋白质。此外，其DNA结合SAP结构域中位于第9 - 24位氨基酸的多碱性基序区域的缺失阻止了与PPIn的相互作用。总之，这些结果与hnRNPU具有在DNA和PPIn相互作用中具有双重功能的多碱性区域一致。
