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Loss of sacsin, a large 520 kDa multidomain protein, causes autosomal recessive spastic ataxia of the Charlevoix-Saguenay, one of the most common childhood-onset recessive ataxias. A prominent feature is abnormal bundling of neurofilaments in many neuronal populations. This study shows the direct involvement of sacsin domains in regulating intermediate filament assembly and dynamics and identifies important domains for alleviating neurofilament bundles in neurons lacking sacsin. Peptides encoding sacsin internal repeat (SIRPT) 1, J-domains, and ubiquitin-like domain modified neurofilament assembly in vivo. The domains with chaperone homology, the SIRPT and the J-domain, had opposite effects, promoting and preventing filament assembly, respectively. In cultured Sacs motor neurons, both the SIRPT1 and J-domain resolved preexisting neurofilament bundles. Increasing expression of heat shock proteins also resolved neurofilament bundles, indicating that this endogenous chaperone system can compensate to some extent for sacsin deficiency.-Gentil, B. J., Lai, G.-T., Menade, M., Larivière, R., Minotti, S., Gehring, K., Chapple, J.-P., Brais, B., Durham, H. D. Sacsin, mutated in the ataxia ARSACS, regulates intermediate filament assembly and dynamics.
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http://dx.doi.org/10.1096/fj.201801556R | DOI Listing |
Biomed Pharmacother
September 2025
Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan.
Liver fibrosis, which eventually leads to cirrhosis, is characterized by excessive accumulation of type I collagen (COL1A), mainly derived from activated hepatic stellate cells (HSCs). Currently, there is no clinical treatments that can directly address this condition. The objectives of this study were to identify a compound that can suppress HSC activation and elucidate the molecular mechanism underlying its action.
View Article and Find Full Text PDFBiochem Biophys Res Commun
August 2025
Department of General Surgery, Tianjin Medical University General Hospital, Tianjin, China; Tianjin General Surgery Institute, Tianjin, China. Electronic address:
Malignant tumors present a major global health burden, as they generally have a poor prognosis, and the efficacy of available treatments is limited. Copine family members (CPNEs) play crucial roles in the regulation of tumor cell proliferation, metastasis, and therapeutic resistance, as well as in tumor diagnosis and prognostic risk stratification. CPNEs can facilitate tumor cell survival by regulating cell cycle progression and cell death.
View Article and Find Full Text PDFJ Biol Inorg Chem
September 2025
Department of Chemistry, University of California, Davis, CA, USA.
Vimentin is a principal intermediate filament (IF) protein that is essential for maintaining cytoskeleton architecture and cellular mechanical integrity. Growing evidence is revealing that metal ions play critical roles in modulating the structure, assembly, and mechanics of vimentin IFs. Despite this, a detailed molecular-level understanding of vimentin-metal interactions and its functional consequences remains incomplete.
View Article and Find Full Text PDFNew Phytol
September 2025
State Key Laboratory of Plant Diversity and Specialty Crops/Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
Heterostyly is a polymorphic floral adaptation controlled by supergenes. The molecular basis of distyly has been investigated in diploid species from several unrelated families, but information is lacking for polyploid systems. Here, we address this knowledge gap in Schizomussaenda henryi, a tetraploid distylous species of Rubiaceae, the family with the greatest number of heterostylous species.
View Article and Find Full Text PDFEur J Cell Biol
August 2025
Institute of Molecular Pharmacology, Medical Faculty, RWTH Aachen University, Wendlingweg 2, Aachen 52074, Germany. Electronic address:
Keratins are the largest and most diverse group of intermediate filament proteins, providing structural integrity and mechanical strength to epithelial cells. Although their assembly as heterodimers is well established, the specific pairing preferences and molecular basis of keratin dimerisation remain largely unknown. Here, we employ a high-throughput computational pipeline that integrates AlphaFold Multimer (AFM) modelling, VoroIF-GNN interaction interface quality assessment, interaction energy calculations and structural comparisons with experimentally solved structures to systematically investigate keratin heterodimerisation and to provide a guideline for further analysis of intermediate filament assembly.
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