Membraneless condensates, such as stress granules (SGs) and processing bodies (P-bodies), have attracted wide attention due to their unique feature of rapid response to stress without first requiring nuclear feedback. In this study, we identify diaphanous-related formin 3 (DIAPH3), an actin nucleator, as a scaffold protein to initiate liquid-liquid phase separation (LLPS) and form abundant cytosolic phase-separated DIAPH3 granules (D-granules) in mammalian cells such as HeLa, HEK293, and fibroblasts under various stress conditions. Neither mRNAs nor known stress-associated condensate markers, such as G3BP1, G3BP2, and TIA1 for SGs and DCP1A for P-bodies, are detected in D-granules. Using overexpression and knockout of DIAPH3, pharmacological interventions, and optogenetics, we further demonstrate that stress-induced D-granules spatially sequester DIAPH3 within the condensation to inhibit the assembly of actin filaments in filopodia. This study reveals that D-granules formed by LLPS act as a regulatory hub for actin cytoskeletal remodeling in response to stress.
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http://dx.doi.org/10.1016/j.celrep.2022.111986 | DOI Listing |
Adv Sci (Weinh)
January 2025
State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
Biomolecular condensates segregate nuclei into discrete regions, facilitating the execution of distinct biological functions. Here, it is identified that the WW domain containing adaptor with coiled-coil (WAC) is localized to nuclear speckles via its WW domain and plays a pivotal role in regulating alternative splicing through the formation of biomolecular condensates via its C-terminal coiled-coil (CC) domain. WAC acts as a scaffold protein and facilitates the integration of RNA-binding motif 12 (RBM12) into nuclear speckles, where RBM12 potentially interacts with the spliceosomal U5 small nuclear ribonucleoprotein (snRNP).
View Article and Find Full Text PDFRev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Since the first Chapter dealt with the well-known charge-charge interactions familiar to biologists, this concluding Chapter introduces some key electrical forces, probably much less familiar, perhaps even unknown. LLPS (liquid liquid phase separation) which we have seen involved in so much of cell biology depends on multivalent, π-π and cation-π electrical forces. How these arise is dealt with here and may be especially useful as an aide memoir to return to when such issues arise within the bulk of the text.
View Article and Find Full Text PDFRev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Pre- and post-synaptic events are regulated by liquid-liquid phase separation and this phenomenon requires multiple electrical forces. Both axonal transport and the organization of postsynaptic excitatory and inhibitory receptors are regulated by LLPS, with its mandatory electrical drivers ultimately determining our cognitive health and capacity.
View Article and Find Full Text PDFRev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Several neurological diseases arise from abnormal protein aggregation within neurones and this is closely regulated by phase separation. One such is motor neurone disease and aberrant aggregation of superoxide dismutase. Again these events are regulated by electrical forces that are examined.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
January 2025
Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA. Electronic address:
The integrated stress response (ISR) is a cellular defense mechanism activated under stress conditions. When the ISR is activated, it slows the production of proteins, the building blocks that cells need to function. Trans-integrated stress response inhibitor (trans-ISRIB) is a compound that can reverse the effects of ISR activation, showing promise for treating neurodegenerative diseases.
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