Autophagy is a highly conserved process by which superfluous or harmful components in eukaryotic cells are degraded by autophagosomes. This cytoprotective mechanism is strongly related to various human diseases, such as cancer, autoimmune diseases, and diabetes. DEAH-box helicase 15 (DHX15), a member of the DEAH box family, is mainly involved in RNA splicing and ribosome maturation. Recently, DHX15 was identified as a tumor-related factor. Although both autophagy and DHX15 are involved in cellular metabolism and cancer progression, their exact relationship and mechanism remain elusive. In this study, we discovered a non-classic function of DHX15 and identified DHX15 as a suppressive protein in autophagy for the first time. We further found that mTORC1 is involved in DHX15-mediated regulation of autophagy and that DHX15 inhibits proliferation of hepatocellular carcinoma (HCC) cells by suppressing autophagy. In conclusion, our study demonstrates a non-classical function of DHX15 as a negative regulator of autophagy related to the mTORC1 pathway and reveals that DHX15-related autophagy dysfunction promotes HCC cell proliferation, indicating that DHX15 may be a target for liver cancer treatment.
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http://dx.doi.org/10.3389/fmed.2020.591736 | DOI Listing |
Nat Commun
November 2024
Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
Mechanisms by which G-patch activators tune the processive multi-tasking ATP-dependent RNA helicase Prp43 (DHX15 in humans) to productively remodel diverse RNA:protein complexes remain elusive. Here, a comparative study between a herein and previously characterized activators, Tma23 and Pxr1, respectively, defines segments that organize Prp43 function during ribosome assembly. In addition to the activating G-patch, we discover an inhibitory segment within Tma23 and Pxr1, I-patch, that restrains Prp43 ATPase activity.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2024
Department of Biotechnology, University of Chemistry and Technology, 166 28 Prague, Czech Republic.
We explored how a simple retrovirus, Mason-Pfizer monkey virus (M-PMV) to facilitate its replication process, utilizes DHX15, a cellular RNA helicase, typically engaged in RNA processing. Through advanced genetic engineering techniques, we showed that M-PMV recruits DHX15 by mimicking cellular mechanisms, relocating it from the nucleus to the cytoplasm to aid in viral assembly. This interaction is essential for the correct packaging of the viral genome and critical for its infectivity.
View Article and Find Full Text PDFFish Shellfish Immunol
October 2024
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, 201306, China. Electronic address:
Takifugu obscurus is a farmed fish of great economic importance in China. The rapid development of T. obscurus aquaculture industry has been accompanied by disease and low-temperature stress, resulting in huge economic losses.
View Article and Find Full Text PDFNature
August 2024
Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria.
Precursor-mRNA (pre-mRNA) splicing requires the assembly, remodelling and disassembly of the multi-megadalton ribonucleoprotein complex called the spliceosome. Recent studies have shed light on spliceosome assembly and remodelling for catalysis, but the mechanism of disassembly remains unclear. Here we report cryo-electron microscopy structures of nematode and human terminal intron lariat spliceosomes along with biochemical and genetic data.
View Article and Find Full Text PDFACS Med Chem Lett
June 2024
Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States.
RNAs are increasingly considered valuable therapeutic targets, and the development of methods to identify and validate both RNA targets and ligands is more important than ever. Here, we utilized a bioinformatic approach to identify a hairpin-containing RNA G-quadruplex (rG4) in the 5' untranslated region (5' UTR) of mRNA. By using a novel competitive small molecule microarray (SMM) approach, we identified a compound that specifically binds to the rG4 ( = 12.
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