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Moraleva A, Deryabin A, Kordyukova M, Polzikov M, Shishova K, Dobrochaeva K, Rubtsov Y, Rubtsova M, Dontsova O, Zatsepina O. Human nucleolar protein SURF6/RRP14 participates in early steps of pre-rRNA processing. PLoS One 2023; 18:e0285833. [PMID: 37450438 PMCID: PMC10348582 DOI: 10.1371/journal.pone.0285833] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/02/2023] [Indexed: 07/18/2023] Open
Abstract
The biogenesis of ribosomes requires tightly controlled transcription and processing of pre-rRNA which comprises ribosomal RNAs forming the core of large and small ribosomal subunits. Early steps of the pre-rRNA processing and assembly of the ribosomal subunits require a large set of proteins that perform folding and nucleolytic cleavage of pre-rRNAs in the nucleoli. Structure and functions of proteins involved in the pre-rRNA processing have been extensively studied in the budding yeast S. cerevisiae. Functional characterization of their human homologues is complicated by the complexity of mammalian ribosomes and increased number of protein factors involved in the ribosomal biogenesis. Homologues of human nucleolar protein SURF6 from yeast and mouse, Rrp14 and Surf6, respectively, had been shown to be involved in the early steps of pre-rRNA processing. Rrp14 works as RNA chaperone in complex with proteins Ssf1 and Rrp15. Human SURF6 knockdown and overexpression were used to clarify a role of SURF6 in the early steps of pre-rRNA processing in human cell lines HeLa and HTC116. By analyzing the abundance of the rRNA precursors in cells with decreased level or overexpression of SURF6, we demonstrated that human SURF6 is involved in the maturation of rRNAs from both small and large ribosomal subunits. Changes in the SURF6 level caused by knockdown or overexpression of the protein do not result in the death of HeLa cells in contrast to murine embryonic fibroblasts, but significantly alter the distribution of cells among the phases of the cell cycle. SURF6 knockdown in both p53 sufficient and p53 deficient HCT116 human cancer cells results in elongation of G0/G1 and shortening of G2/M phase. This surprising result suggests p53 independence of SURF6 effects on the cell cycle and possible multiple functions of SURF6. Our data point to the shift from pathway 1 to pathway 2 of the rRNA biogenesis caused by the SURF6 knockdown and its likely association with p53 pathway.
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Affiliation(s)
- Anastasiia Moraleva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
| | - Alexander Deryabin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
| | - Maria Kordyukova
- Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russian Federation
| | - Mikhail Polzikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
| | - Kseniya Shishova
- Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russian Federation
| | - Kira Dobrochaeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
| | - Yury Rubtsov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
| | - Maria Rubtsova
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Olga Dontsova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russian Federation
- SkolTech, Moscow, Russian Federation
| | - Olga Zatsepina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russian Federation
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Ferrolino MC, Mitrea DM, Michael JR, Kriwacki RW. Compositional adaptability in NPM1-SURF6 scaffolding networks enabled by dynamic switching of phase separation mechanisms. Nat Commun 2018; 9:5064. [PMID: 30498217 PMCID: PMC6265330 DOI: 10.1038/s41467-018-07530-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/08/2018] [Indexed: 12/18/2022] Open
Abstract
The nucleolus, the site for ribosome biogenesis contains hundreds of proteins and several types of RNA. The functions of many non-ribosomal nucleolar proteins are poorly understood, including Surfeit locus protein 6 (SURF6), an essential disordered protein with roles in ribosome biogenesis and cell proliferation. SURF6 co-localizes with Nucleophosmin (NPM1), a highly abundant protein that mediates the liquid-like features of the granular component region of the nucleolus through phase separation. Here, we show that electrostatically-driven interactions between disordered regions of NPM1 and SURF6 drive liquid-liquid phase separation. We demonstrate that co-existing heterotypic (NPM1-SURF6) and homotypic (NPM1-NPM1) scaffolding interactions within NPM1-SURF6 liquid-phase droplets dynamically and seamlessly interconvert in response to variations in molecular crowding and protein concentrations. We propose a mechanism wherein NPM1-dependent nucleolar scaffolds are modulated by non-ribosomal proteins through active rearrangements of interaction networks that can possibly contribute to the directionality of ribosomal biogenesis within the liquid-like nucleolus. The nucleolus is a membrane-less organelle and both Nucleophosmin (NPM1) and Surfeit locus protein 6 (SURF6) are abundant proteins within the nucleolus. Here the authors employ biophysical methods to study the properties of NPM1-S6N droplets and provide insights into the role of SURF6 in maintaining and modulating the liquid-like structure of the nucleolus.
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Affiliation(s)
- Mylene C Ferrolino
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Diana M Mitrea
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - J Robert Michael
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA. .,Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA.
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Moraleva A, Magoulas C, Polzikov M, Hacot S, Mertani HC, Diaz JJ, Zatsepina O. Involvement of the specific nucleolar protein SURF6 in regulation of proliferation and ribosome biogenesis in mouse NIH/3T3 fibroblasts. Cell Cycle 2017; 16:1979-1991. [PMID: 28873013 DOI: 10.1080/15384101.2017.1371880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The nucleolar proteins which link cell proliferation to ribosome biogenesis are regarded to be potentially oncogenic. Here, in order to examine the involvement of an evolutionary conserved nucleolar protein SURF6/Rrp14 in proliferation and ribosome biogenesis in mammalian cells, we established stably transfected mouse NIH/3T3 fibroblasts capable of conditional overexpression of the protein. Cell proliferation was monitored in real-time, and various cell cycle parameters were quantified based on flow cytometry, Br-dU-labeling and conventional microscopy data. We show that overexpression of SURF6 accelerates cell proliferation and promotes transition through all cell cycle phases. The most prominent SURF6 pro-proliferative effects include a significant reduction of the population doubling time, from 19.8 ± 0.7 to 16.2 ± 0.5 hours (t-test, p < 0.001), and of the length of cell division cycle, from 17.6 ± 0.6 to 14.0 ± 0.4 hours (t-test, p < 0.001). The later was due to the shortening of all cell cycle phases but the length of G1 period was reduced most, from 5.7 ± 0.4 to 3.8 ± 0.3 hours, or by ∼30%, (t-test, p < 0.05). By Northern blots and qRT-PCR, we further showed that the acceleration of cell proliferation was concomitant with an accumulation of rRNA species along both ribosomal subunit maturation pathways. It is evident, therefore, that like the yeast homologue Rrp14, mammalian SURF6 is involved in various steps of rRNA processing during ribosome biogenesis. We concluded that SURF6 is a novel positive regulator of proliferation and G1/S transition in mammals, implicating that SURF6 is a potential oncogenic protein, which can be further studied as a putative target in anti-cancer therapy.
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Affiliation(s)
- Anastasiia Moraleva
- a Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences , Moscow , Russian Federation
| | - Charalambos Magoulas
- b Centre for Investigative and Diagnostic Oncology, Department of Natural Sciences, School of Science and Technology , Middlesex University , London , United Kingdom
| | - Mikhail Polzikov
- a Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences , Moscow , Russian Federation
| | - Sabine Hacot
- c Centre de Recherche en Cancérologie de Lyon, UMR INSERM 1052-CNRS 5286, Centre Léon Bérard , Université Claude Bernard Lyon I, Université de Lyon , Lyon , France
| | - Hichem C Mertani
- c Centre de Recherche en Cancérologie de Lyon, UMR INSERM 1052-CNRS 5286, Centre Léon Bérard , Université Claude Bernard Lyon I, Université de Lyon , Lyon , France
| | - Jean-Jacques Diaz
- c Centre de Recherche en Cancérologie de Lyon, UMR INSERM 1052-CNRS 5286, Centre Léon Bérard , Université Claude Bernard Lyon I, Université de Lyon , Lyon , France
| | - Olga Zatsepina
- a Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences , Moscow , Russian Federation.,c Centre de Recherche en Cancérologie de Lyon, UMR INSERM 1052-CNRS 5286, Centre Léon Bérard , Université Claude Bernard Lyon I, Université de Lyon , Lyon , France
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