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Asymmetric positioning of the mitotic spindle is a fundamental process responsible for creating sibling cell size asymmetry; however, how the cortex causes the depolymerization of astral microtubules during asymmetric spindle positioning has remained elusive. Early ascidian embryos possess a large cortical subdomain of endoplasmic reticulum (ER) that causes asymmetric spindle positioning driving unequal cell division. Here we show that the microtubule depolymerase Kif2 localizes to this subdomain of cortical ER. Rapid live-cell imaging reveals that microtubules are less abundant in the subdomain of cortical ER. Inhibition of Kif2 function prevents the development of mitotic aster asymmetry and spindle pole movement towards the subdomain of cortical ER, whereas locally increasing microtubule depolymerization causes exaggerated asymmetric spindle positioning. This study shows that the microtubule depolymerase Kif2 is localized to a cortical subdomain of endoplasmic reticulum that is involved in asymmetric spindle positioning during unequal cell division.Early ascidian embryos have a cortical subdomain of endoplasmic reticulum (ER) that controls asymmetric spindle positioning driving unequal cell division. Here the authors show that the microtubule depolymerase Kif2 is localized to a cortical subdomain of the ER that is involved in asymmetric spindle positioning.
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http://dx.doi.org/10.1038/s41467-017-01048-8 | DOI Listing |
Structure
September 2025
Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada. Electronic address:
Kinesin-8 motors regulate kinetochore-microtubule dynamics and control spindle length and positioning. Certain isoforms achieve this by traversing microtubules, accumulating at plus-ends, and depolymerizing terminal αβ-tubulin subunits. While the kinesin-8 motor domain is well characterized, the tail domain regions are less understood.
View Article and Find Full Text PDFMol Cell Endocrinol
September 2025
Reproductive Medicine Center, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China.
RNA-binding proteins (RBPs) are critical regulators of post-transcriptional gene expression and RNA processing during mammalian oocyte development. SERPINE1 mRNA-binding protein 1 (SERBP1), a conserved RNA-binding protein (RBP), exhibits prominent expression in the female reproductive system and throughout oogenesis. Conditional deletion of Serbp1 using oocyte-specific Zp3/Gdf9-Cre drivers resulted in arrested oocyte growth, female infertility, and failure of blastocyst formation from two-cell embryos.
View Article and Find Full Text PDFChemMedChem
August 2025
Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany.
Binaphthyls usually serve as key chiral ligands in catalysts for asymmetric syntheses, having been reported in thousands of published reactions. Herein, the discovery that atropisomeric (R)-[1,1'-binaphthalene]-2,2'-diamine (R-BINAM, 1(R)) is a moderately potent spindle poison, causing antiproliferation, depolymerization of microtubules, multipolar spindles, pericentriolar material (PCM) fragmentation, mitotic catastrophe, multinucleated cells, and apoptosis in cancer and normal human cell lines, is reported. Furthermore, the resulting abnormalities resemble those induced by microtubule-depolymerizing agents (MDAs) such as colchicine.
View Article and Find Full Text PDFNPJ Syst Biol Appl
August 2025
Div. of Biology, IISER Pune, Dr. Homi Bhabha Road, Pashan, Pune, India.
The first embryonic division of Caenorhabditis elegans is a model for asymmetric cell division, and identifying the stages of cell division across related species could improve our understanding of the divergence of cellular events and mechanisms. Comparative microscopy of evolutionarily divergent species continues to rely on label-free differential interference contrast (DIC) microscopy due to technical challenges in molecular tagging, with the identification of cell division stages still relying on label-free microscopy. Here, we compare multiple deep convolutional neural networks (CNNs) trained to automate cell stage classification in DIC microscopy movies and interpret the results, with code and classification weights released as OpenSource.
View Article and Find Full Text PDFAdv Healthc Mater
August 2025
Key Laboratory of Advanced Materials of Ministry of Education of China, Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science & Engineering, Tsinghua University, Beijing, 100084, China.
Nanoscales that mimic natural cascade catalytic reactions through simple procedures, demonstrating high efficiency, have attracted extensive interest in the antibacterial field. However, the rational design of nanostructures and the improvement of their catalytic efficiency remain challenging. Herein, spindle-shaped Ni-Au Janus nanocomposites (JANs) are synthesized with asymmetric catalytic duality and NIR-responsive photothermal activation.
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