A dynamic link between H/ACA snoRNP components and cytoplasmic stress granules

• Published in: Biochimica et biophysica acta. Molecular cell research Vol. 1866; no. 12; p. 118529
• Main Authors: Belli, Valentina, Matrone, Nunzia, Sagliocchi, Serena, Incarnato, Rosa, Conte, Andrea, Pizzo, Elio, Turano, Mimmo, Angrisani, Alberto, Furia, Maria
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2019
• Subjects: Cell Cycle Proteins - genetics; Cell Cycle Proteins - isolation & purification; Cell Cycle Proteins - metabolism; Cytoplasmic Granules - metabolism; Dyskerin; HeLa Cells; Humans; Nuclear Proteins - genetics; Nuclear Proteins - isolation & purification; Nuclear Proteins - metabolism; Nucleolus; Ribonucleoproteins, Small Nucleolar - metabolism; Ribosome; RNP bodies; snoRNPs; Stress response; Tumor Cells, Cultured; Ribosome; Nucleolus; Stress response; Dyskerin; snoRNPs; RNP bodies
• ISSN: 0167-4889; 1879-2596
• DOI: 10.1016/j.bbamcr.2019.118529

Many cell stressors block protein translation, inducing formation of cytoplasmic aggregates. These aggregates, named stress granules (SGs), are composed by translationally stalled ribonucleoproteins and their assembly strongly contributes to cell survival. Composition and dynamics of SGs are thus important starting points for identifying critical factors of the stress response. In the present study we link components of the H/ACA snoRNP complexes, highly concentrated in the nucleoli and the Cajal bodies, to SG composition. H/ACA snoRNPs are composed by a core of four highly conserved proteins -dyskerin, Nhp2, Nop10 and Gar1- and are involved in several fundamental processes, including ribosome biogenesis, RNA pseudouridylation, stabilization of small nucleolar RNAs and telomere maintenance. By taking advantage of cells overexpressing a dyskerin splice variant undergoing a dynamic intracellular trafficking, we were able to show that H/ACA snoRNP components can participate in SG formation, this way contributing to the stress response and perhaps transducing signals from the nucleus to the cytoplasm. Collectively, our results show for the first time that H/ACA snoRNP proteins can have additional non-nuclear functions, either independently or interacting with each other, thus further strengthening the close relationship linking nucleolus to SG composition.
•A variant dyskerin isoform exhibits a dual nucleo-cytoplasmic localization.•A dyskerin isoform is recruited to stress granules and other cytoplasmic RNP foci.•Components of H/ACA snoRNPs can have extra-nuclear functions.•Core proteins of H/ACA snoRNPs are new players in stress granules composition.