98%
921
2 minutes
20
The last steps in mRNA export and remodeling are performed by the Nup82 complex, a large conserved assembly at the cytoplasmic face of the nuclear pore complex (NPC). By integrating diverse structural data, we have determined the molecular architecture of the native Nup82 complex at subnanometer precision. The complex consists of two compositionally identical multiprotein subunits that adopt different configurations. The Nup82 complex fits into the NPC through the outer ring Nup84 complex. Our map shows that this entire 14-MDa Nup82-Nup84 complex assembly positions the cytoplasmic mRNA export factor docking sites and messenger ribonucleoprotein (mRNP) remodeling machinery right over the NPC's central channel rather than on distal cytoplasmic filaments, as previously supposed. We suggest that this configuration efficiently captures and remodels exporting mRNP particles immediately upon reaching the cytoplasmic side of the NPC.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5130164 | PMC |
http://dx.doi.org/10.1016/j.cell.2016.10.028 | 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 PDFKaohsiung J Med Sci
September 2025
Department of Gynecology, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China.
Ferroptosis resistance is a key player in cervical cancer (CC) development. Hypoxia is a negative factor affecting CC treatment by inducing ferroptosis resistance. Our study aimed to investigate the detailed mechanisms of hypoxia-induced ferroptosis resistance in CC cells.
View Article and Find Full Text PDFBackground: A hallmark of the eukaryotic cell is the regulated transport between the nucleus and cytoplasm, which is mediated by a multi-subunit protein assembly called the nuclear pore complex (NPC). While its overall architecture has been preserved across eukaryotes, variations in NPC structure appear to have tuned its function in different organisms. Outside of a handful of model systems, the NPC has not been comprehensively studied.
View Article and Find Full Text PDFUnlabelled: Heterogenous transcription start site (TSS) usage dictates the structure and function of unspliced HIV-1 RNAs (usRNA). We and others have previously reported that expression and Rev/CRM1-mediated nuclear export of HIV-1 usRNA in macrophages activates MDA5, MAVS, and innate immune signaling cascades. In this study, we reveal that MDA5 sensing of viral usRNA is strictly determined by TSS, 5' leader structure, and RNA function.
View Article and Find Full Text PDF