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Borkúti P, Kristó I, Szabó A, Kovács Z, Vilmos P. FERM domain-containing proteins are active components of the cell nucleus. Life Sci Alliance 2024; 7:e202302489. [PMID: 38296350 PMCID: PMC10830384 DOI: 10.26508/lsa.202302489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/05/2024] Open
Abstract
The FERM domain is a conserved and widespread protein module that appeared in the common ancestor of amoebae, fungi, and animals, and is therefore now found in a wide variety of species. The primary function of the FERM domain is localizing to the plasma membrane through binding lipids and proteins of the membrane; thus, for a long time, FERM domain-containing proteins (FDCPs) were considered exclusively cytoskeletal. Although their role in the cytoplasm has been extensively studied, the recent discovery of the presence and importance of cytoskeletal proteins in the nucleus suggests that FDCPs might also play an important role in nuclear function. In this review, we collected data on their nuclear localization, transport, and possible functions, which are still scattered throughout the literature, with special regard to the role of the FERM domain in these processes. With this, we would like to draw attention to the exciting, new dimension of the role of FDCPs, their nuclear activity, which could be an interesting novel direction for future research.
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Affiliation(s)
| | | | - Anikó Szabó
- HUN-REN Biological Research Centre, Szeged, Hungary
| | - Zoltán Kovács
- HUN-REN Biological Research Centre, Szeged, Hungary
- Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Péter Vilmos
- HUN-REN Biological Research Centre, Szeged, Hungary
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Kovács Z, Bajusz C, Szabó A, Borkúti P, Vedelek B, Benke R, Lipinszki Z, Kristó I, Vilmos P. A bipartite NLS motif mediates the nuclear import of Drosophila moesin. Front Cell Dev Biol 2024; 12:1206067. [PMID: 38450250 PMCID: PMC10915024 DOI: 10.3389/fcell.2024.1206067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 02/08/2024] [Indexed: 03/08/2024] Open
Abstract
The ERM protein family, which consists of three closely related proteins in vertebrates, ezrin, radixin, and moesin (ERM), is an ancient and important group of cytoplasmic actin-binding and organizing proteins. With their FERM domain, ERMs bind various transmembrane proteins and anchor them to the actin cortex through their C-terminal F-actin binding domain, thus they are major regulators of actin dynamics in the cell. ERMs participate in many fundamental cellular processes, such as phagocytosis, microvilli formation, T-cell activation and tumor metastasis. We have previously shown that, besides its cytoplasmic activities, the single ERM protein of Drosophila melanogaster, moesin, is also present in the cell nucleus, where it participates in gene expression and mRNA export. Here we study the mechanism by which moesin enters the nucleus. We show that the nuclear import of moesin is an NLS-mediated, active process. The nuclear localization sequence of the moesin protein is an evolutionarily highly conserved, conventional bipartite motif located on the surface of the FERM domain. Our experiments also reveal that the nuclear import of moesin does not require PIP2 binding or protein activation, and occurs in monomeric form. We propose, that the balance between the phosphorylated and non-phosphorylated protein pools determines the degree of nuclear import of moesin.
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Affiliation(s)
- Zoltán Kovács
- HUN-REN Biological Research Centre, Szeged, Hungary
- Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Csaba Bajusz
- HUN-REN Biological Research Centre, Szeged, Hungary
| | - Anikó Szabó
- HUN-REN Biological Research Centre, Szeged, Hungary
| | | | | | - Réka Benke
- HUN-REN Biological Research Centre, Szeged, Hungary
| | - Zoltán Lipinszki
- HUN-REN Biological Research Centre, Institute of Biochemistry, MTA SZBK Lendület Laboratory of Cell Cycle Regulation, Szeged, Hungary
| | | | - Péter Vilmos
- HUN-REN Biological Research Centre, Szeged, Hungary
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Kristó I, Borkúti P, Kovács Z, Szabó A, Szikora S, Vilmos P. Detection of Actin in Nuclear Protein Fraction Isolated from Adult Drosophila Ovary. Methods Mol Biol 2023; 2626:353-364. [PMID: 36715915 DOI: 10.1007/978-1-0716-2970-3_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Much evidence supports the presence of cytoskeletal elements in the nucleus; however, the exact functions of these proteins in the nucleus are still uncertain. Of the cytoskeletal proteins, the activity and biological significance of nuclear actin has been the most extensively researched. It is now clear that actin performs essential tasks both in the cytoplasm and the nucleus, and that the dynamic balance between the large cytoplasmic and the significantly smaller nuclear actin pools is maintained by robust transport mechanisms. Therefore, the compartment-specific manipulation or investigation of actin has been an enormous challenge. Here, we present a protocol for the detection of actin in isolated nuclear protein fractions from Drosophila ovaries.
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Affiliation(s)
- Ildikó Kristó
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Péter Borkúti
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary.,Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Zoltán Kovács
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary.,Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Anikó Szabó
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Szilárd Szikora
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Péter Vilmos
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary.
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Borkúti P, Kristó I, Szabó A, Bajusz C, Kovács Z, Réthi-Nagy Z, Lipinszki Z, Lukácsovich T, Bogdan S, Vilmos P. Parallel import mechanisms ensure the robust nuclear localization of actin in Drosophila. Front Mol Biosci 2022; 9:963635. [PMID: 36060241 PMCID: PMC9437273 DOI: 10.3389/fmolb.2022.963635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/29/2022] [Indexed: 11/25/2022] Open
Abstract
Actin, as an ancient and fundamental protein, participates in various cytoplasmic as well as nuclear functions in eukaryotic cells. Based on its manifold tasks in the nucleus, it is a reasonable assumption that the nuclear presence of actin is essential for the cell, and consequently, its nuclear localization is ensured by a robust system. However, today only a single nuclear import and a single nuclear export pathway is known which maintain the dynamic balance between cytoplasmic and nuclear actin pools. In our work, we tested the robustness of the nuclear import of actin, and investigated whether the perturbations of nuclear localization affect the viability of the whole organism. For this aim, we generated a genetic system in Drosophila, in which we rescued the lethal phenotype of the null mutation of the Actin5C gene with transgenes that express different derivatives of actin, including a Nuclear Export Signal (NES)-tagged isoform which ensures forced nuclear export of the protein. We also disrupted the SUMOylation site of actin, suggested earlier to be responsible for nuclear retention, and eliminated the activity of the single nuclear import factor dedicated to actin. We found that, individually, none of the above mentioned manipulations led to a notable reduction in nuclear actin levels and thus, fully rescued lethality. However, the NES tagging of actin, together with the knock out of its importin, significantly reduced the amount of nuclear actin and induced lethality, confirming that the presence of actin in the nucleus is essential, and thereby, over-secured. Supporting this, we identified novel nuclear importins specific to actin, which sheds light on the mechanism behind the robustness of nuclear localization of actin, and supports the idea of essentiality of its nuclear functions.
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Affiliation(s)
- Péter Borkúti
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
- Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Ildikó Kristó
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Anikó Szabó
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Csaba Bajusz
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Zoltán Kovács
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
- Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Zsuzsánna Réthi-Nagy
- Biological Research Centre, Institute of Biochemistry, MTA SZBK Lendület Laboratory of Cell Cycle Regulation, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Zoltán Lipinszki
- Biological Research Centre, Institute of Biochemistry, MTA SZBK Lendület Laboratory of Cell Cycle Regulation, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | | | - Sven Bogdan
- Department of Molecular Cell Physiology, Institute of Physiology and Pathophysiology, Philipps-University, Marburg, Germany
| | - Péter Vilmos
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
- *Correspondence: Péter Vilmos,
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Bajusz C, Kristó I, Abonyi C, Venit T, Vedelek V, Lukácsovich T, Farkas A, Borkúti P, Kovács Z, Bajusz I, Marton A, Vizler C, Lipinszki Z, Sinka R, Percipalle P, Vilmos P. The nuclear activity of the actin-binding Moesin protein is necessary for gene expression in Drosophila. FEBS J 2021; 288:4812-4832. [PMID: 33606336 DOI: 10.1111/febs.15779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 01/22/2021] [Accepted: 02/18/2021] [Indexed: 11/30/2022]
Abstract
Ezrin-Radixin-Moesin (ERM) proteins play an essential role in the cytoplasm by cross-linking actin filaments with plasma membrane proteins. Research has identified the nuclear localization of ERMs, as well as the involvement of a single Drosophila ERM protein, Moesin, in nuclear mRNA exports. However, the question of how important the nuclear activity of ERM proteins are for the life of an organism has so far not been explored. Here, we present the first attempt to reveal the in vivo relevance of nuclear localization of Moesin in Drosophila. With the help of a nuclear export signal, we decreased the amount of Moesin in the nuclei of the animals. Furthermore, we observed various developmental defects, demonstrating the importance of ERM function in the nucleus for the first time. Transcriptome analysis of the mutant flies revealed that the lack of nuclear Moesin function leads to expression changes in nearly 700 genes, among them heat-shock genes. This result together with additional findings revealed that in Drosophila the expression of protein chaperones requires the nuclear functions of Moesin. DATABASE: GEO accession number: GSE155778.
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Affiliation(s)
- Csaba Bajusz
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Hungary
| | - Ildikó Kristó
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Csilla Abonyi
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Tomáš Venit
- Biology Program, Science Division, New York University Abu Dhabi, UAE
| | | | | | - Attila Farkas
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Péter Borkúti
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary.,Doctoral School of Multidisciplinary Medical Science, University of Szeged, Hungary
| | - Zoltán Kovács
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary.,Doctoral School of Multidisciplinary Medical Science, University of Szeged, Hungary
| | - Izabella Bajusz
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Annamária Marton
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Csaba Vizler
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
| | - Zoltán Lipinszki
- Lendület Laboratory of Cell Cycle Regulation, ELKH, Biological Research Centre, Szeged, Hungary
| | - Rita Sinka
- Department of Genetics, University of Szeged, Hungary
| | - Piergiorgio Percipalle
- Biology Program, Science Division, New York University Abu Dhabi, UAE.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Sweden
| | - Péter Vilmos
- Eötvös Loránd Research Network (ELKH), Biological Research Centre, Szeged, Hungary
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