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Hypoxia-inducible factor 1alpha (HIF1alpha) is a critical transcriptional factor for inducing tumor metastasis, and stabilized under hypoxia but degraded by von Hippel-Lindau protein (pVHL) under normoxia. For the maximal degradation of HIF1alpha, it must be exported to the cytoplasm via an unidentified transporter. Here, we demonstrate that vitamin D3 up-regulated protein 1 (VDUP1) associates with the beta-domain of pVHL and enhances the interaction between pVHL and HIF1alpha to promote the nuclear export and degradation of HIF1alpha hypoxia-independently. Blocking of VDUP1 translocation either by leptomycin B or by nuclear export signal mutation inhibited the nuclear export of pVHL/HIF1alpha and relieved the destabilization of HIF1alpha. VDUP1 suppressed cell invasiveness and tumor metastasis, which were also recovered by blocking of nuclear export. Taken together, these findings indicate that VDUP1 is a novel tumor suppressor which mediates the nuclear export of pVHL/HIF1alpha complex to destabilize HIF1alpha.
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http://dx.doi.org/10.1016/j.bbamcr.2007.10.012 | DOI Listing |
Nat Rev Mol Cell Biol
September 2025
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
The defining property of eukaryotic cells is the storage of heritable genetic material in a nuclear compartment. For eukaryotic cells to carry out the myriad biochemical processes necessary for their function, macromolecules must be efficiently exchanged between the nucleus and cytoplasm. The nuclear pore complex (NPC) - which is a massive assembly of ~35 different proteins present in multiple copies totalling ~1,000 protein subunits and architecturally conserved across eukaryotes - establishes a size-selective channel for regulated bidirectional transport of folded macromolecules and macromolecular assemblies across the nuclear envelope.
View Article and Find Full Text PDFBiochem J
September 2025
Cancer Research UK Scotland Institute, Glasgow, G61 1BD, U.K.
RNA cap formation on RNA polymerase II transcripts is regulated by cellular signalling pathways during development and differentiation, adaptive and innate immune responses, during the cell cycle and in response to oncogene deregulation. Here, we discuss how the RNA cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), functions to complete the 7-methyl-guanosine or m7G cap. The mechanisms by which RNMT is regulated by signalling pathways, co-factors and other enzymes are explored.
View Article and Find Full Text PDFJ Virol
September 2025
Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan.
Double-stranded RNA (dsRNA), which induces an innate immune response against viral infections, is rarely detected in influenza A virus (IAV)-infected cells. Nevertheless, we previously reported that the influenza A viral ribonucleoprotein (vRNP) complex generates looped dsRNAs during RNA synthesis . This finding suggests that IAV possesses a specific mechanism for sequestering dsRNA within infected cells, thereby enabling viral evasion of the innate immune response.
View Article and Find Full Text PDFNAR Genom Bioinform
September 2025
Department of Internal Medicine, Nephrology Division, University of Michigan, Ann Arbor 48109 MI, United States.
The dynamics of transcriptional elongation influence many biological activities, such as RNA splicing, polyadenylation, and nuclear export. To quantify the elongation rate, a typical method is to treat cells with drugs that inhibit RNA polymerase II (Pol II) from entering the gene body and then track Pol II using Pro-seq or Gro-seq. However, the downstream data analysis is challenged by the problem of identifying the transition point between the gene regions inhibited by the drug and not, which is necessary to calculate the transcription rate.
View Article and Find Full Text PDFAppl Radiat Isot
September 2025
Department of Geological Sciences, Faculty of Science, Galala University, New Galala City, 43511, Suez, Egypt.
Gamma-ray spectrometric analysis is used to measure and assess potential hazards of natural radiation in commercial brands of Egyptian granite used locally and for export. Ratio of eU/eTh of the Halayeb granite varieties amounts ≥1 whereas this ratio lies in the range of 0.5-1 for Gandolla and Hurgada red.
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