The COP9 signalosome (CSN) is an eight-subunit complex that regulates multiple signaling and cell cycle pathways. Here we link the CSN to the degradation of Cyclin E, which promotes the G1-S transition in the cell cycle and then is rapidly degraded by the ubiquitin-proteasome pathway. Using CSN4 and CSN5/Jab1 mutants, we show that the CSN acts during Drosophila oogenesis to remove Nedd8 from Cullin1, a subunit of the SCF ubiquitin ligase. Overexpression of Cyclin E causes similar defects as mutations in CSN or SCF(Ago) subunits: extra divisions or, in contrast, cell cycle arrest and polyploidy. Because the phenotypes are so similar and because CSN and Cyclin E mutations reciprocally suppress each other, Cyclin E appears to be the major target of the CSN during early oogenesis. Genetic interactions among CSN, SCF, and proteasome subunits further confirm CSN involvement in ubiquitin-mediated Cyclin E degradation.
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http://dx.doi.org/10.1016/s1534-5807(03)00121-7 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Shenzhen Key Laboratory of Biomolecular Assembling and Regulation, Department of Neuroscience, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
Ankyrin Repeat Domain-containing Protein 11 () is a causative gene for KBG syndrome, a significant risk factor for Cornelia de Lange syndrome (CdLS), and a highly confident autism spectrum disorder gene. Mutations of lead to developmental abnormalities in multiple organs/tissues including the brain, craniofacial and skeletal bones, and tooth structures with unknown mechanism(s). Here, we find that ANKRD11, via a short peptide fragment in its N-terminal region, binds to the cohesin complex with a high affinity, implicating why mutation can cause CdLS.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing 100193, China.
Light serves as an energy source for cell division and expansion during fruit development. Cell expansion significantly influences fruit size and is closely linked to endoreduplication, a unique cell cycle variation characterized by DNA replication without cytokinesis. Paradoxically, under conditions of ample photosynthates, light signaling suppresses cell expansion.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115.
Epstein-Barr virus (EBV) establishes persistent infection, causes infectious mononucleosis, is a major trigger for multiple sclerosis and contributes to multiple cancers. Yet, knowledge remains incomplete about how the virus remodels host B cells to support lytic replication. We previously identified that EBV lytic replication results in selective depletion of plasma membrane (PM) B cell receptor (BCR) complexes, composed of immunoglobulin and the CD79A and CD79B signaling chains.
View Article and Find Full Text PDFDokl Biochem Biophys
January 2025
Institute of Biomedical Problems, Russian Academy of Sciences, 123007, Moscow, Russia.
One of the most obvious manifestations of the negative impact of space flight factors on the human physiology is osteopenia. With the active development of manned space flights and the increase in the duration of humans' persistence in weightlessness, there is a growing need to understand the mechanisms of changes occurring at the cellular level involved in the replenishment of bone tissue. Using the RNA sequencing method, changes in the transcriptome profile of MMSCs were studied after a 5-day simulation of the microgravity effects.
View Article and Find Full Text PDFDokl Biochem Biophys
January 2025
State Research Center-Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, 123098, Moscow, Russia.
Background: The effects of ionizing radiation (IR) involve a highly orchestrated series of events in cells, including DNA damage and repair, cell death, and changes in the level of proliferation associated with the stage of the cell cycle. A large number of existing studies in literature have examined the activity of genes and their regulators in mammalian cells in response to high doses of ionizing radiation. Although there are many studies, the research in effect of low doses of ionizing radiation remains limited.
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