1
|
Deolal P, Scholz J, Ren K, Bragulat-Teixidor H, Otsuka S. Sculpting nuclear envelope identity from the endoplasmic reticulum during the cell cycle. Nucleus 2024; 15:2299632. [PMID: 38238284 PMCID: PMC10802211 DOI: 10.1080/19491034.2023.2299632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024] Open
Abstract
The nuclear envelope (NE) regulates nuclear functions, including transcription, nucleocytoplasmic transport, and protein quality control. While the outer membrane of the NE is directly continuous with the endoplasmic reticulum (ER), the NE has an overall distinct protein composition from the ER, which is crucial for its functions. During open mitosis in higher eukaryotes, the NE disassembles during mitotic entry and then reforms as a functional territory at the end of mitosis to reestablish nucleocytoplasmic compartmentalization. In this review, we examine the known mechanisms by which the functional NE reconstitutes from the mitotic ER in the continuous ER-NE endomembrane system during open mitosis. Furthermore, based on recent findings indicating that the NE possesses unique lipid metabolism and quality control mechanisms distinct from those of the ER, we explore the maintenance of NE identity and homeostasis during interphase. We also highlight the potential significance of membrane junctions between the ER and NE.
Collapse
Affiliation(s)
- Pallavi Deolal
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
| | - Julia Scholz
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Kaike Ren
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Helena Bragulat-Teixidor
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Shotaro Otsuka
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Medical University of Vienna, Center for Medical Biochemistry, Department of Molecular Biology, Vienna, Austria
| |
Collapse
|
2
|
Fujimoto T. Nuclear lipid droplet: Guardian of nuclear membrane lipid homeostasis? Curr Opin Cell Biol 2024; 88:102370. [PMID: 38744005 DOI: 10.1016/j.ceb.2024.102370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 04/22/2024] [Indexed: 05/16/2024]
Abstract
Lipid droplets (LDs) are cytoplasmic organelles, but they are also found within the nucleus in small numbers. Nuclear LDs that form at the inner nuclear membrane (INM) often increase in response to perturbation in phosphatidic acid (PA) and/or diacylglycerol (DAG), both implicated in various INM functions. Nuclear LDs also increase upon downregulation of seipin, a protein that can trap PA and DAG in the endoplasmic reticulum. Notably, both PA and DAG appear to be more densely distributed on the surface of nuclear LDs than in the INM. I propose that nuclear LDs play a role in regulating the PA and DAG level in the INM, thereby contributing to the lipid homeostasis in this compartment.
Collapse
Affiliation(s)
- Toyoshi Fujimoto
- Laboratory of Molecular Cell Biology, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan. mailto:
| |
Collapse
|
3
|
Hirano Y, Sato T, Miura A, Kubota Y, Shindo T, Fukase K, Fukagawa T, Kabayama K, Haraguchi T, Hiraoka Y. Disordered region of nuclear membrane protein Bqt4 recruits phosphatidic acid to the nuclear envelope to maintain its structural integrity. J Biol Chem 2024; 300:107430. [PMID: 38825008 DOI: 10.1016/j.jbc.2024.107430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/09/2024] [Accepted: 05/18/2024] [Indexed: 06/04/2024] Open
Abstract
The nuclear envelope (NE) is a permeable barrier that maintains nuclear-cytoplasmic compartmentalization and ensures nuclear function; however, it ruptures in various situations such as mechanical stress and mitosis. Although the protein components for sealing a ruptured NE have been identified, the mechanism by which lipid components are involved in this process remains to be elucidated. Here, we found that an inner nuclear membrane (INM) protein Bqt4 directly interacts with phosphatidic acid (PA) and serves as a platform for NE maintenance in the fission yeast Schizosaccharomyces pombe. The intrinsically disordered region (IDR) of Bqt4, proximal to the transmembrane domain, binds to PA and forms a solid aggregate in vitro. Excessive accumulation of Bqt4 IDR in INM results in membrane overproliferation and lipid droplet formation in the nucleus, leading to centromere dissociation from the NE and chromosome missegregation. Our findings suggest that Bqt4 IDR controls nuclear membrane homeostasis by recruiting PA to the INM, thereby maintaining the structural integrity of the NE.
Collapse
Affiliation(s)
- Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
| | - Tsukino Sato
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Ayane Miura
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Yoshino Kubota
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | | | - Koichi Fukase
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Kazuya Kabayama
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
| |
Collapse
|
4
|
Kazanietz MG, Cooke M. Protein kinase C signaling "in" and "to" the nucleus: Master kinases in transcriptional regulation. J Biol Chem 2024; 300:105692. [PMID: 38301892 PMCID: PMC10907189 DOI: 10.1016/j.jbc.2024.105692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/03/2024] Open
Abstract
PKC is a multifunctional family of Ser-Thr kinases widely implicated in the regulation of fundamental cellular functions, including proliferation, polarity, motility, and differentiation. Notwithstanding their primary cytoplasmic localization and stringent activation by cell surface receptors, PKC isozymes impel prominent nuclear signaling ultimately impacting gene expression. While transcriptional regulation may be wielded by nuclear PKCs, it most often relies on cytoplasmic phosphorylation events that result in nuclear shuttling of PKC downstream effectors, including transcription factors. As expected from the unique coupling of PKC isozymes to signaling effector pathways, glaring disparities in gene activation/repression are observed upon targeting individual PKC family members. Notably, specific PKCs control the expression and activation of transcription factors implicated in cell cycle/mitogenesis, epithelial-to-mesenchymal transition and immune function. Additionally, PKCs isozymes tightly regulate transcription factors involved in stepwise differentiation of pluripotent stem cells toward specific epithelial, mesenchymal, and hematopoietic cell lineages. Aberrant PKC expression and/or activation in pathological conditions, such as in cancer, leads to profound alterations in gene expression, leading to an extensive rewiring of transcriptional networks associated with mitogenesis, invasiveness, stemness, and tumor microenvironment dysregulation. In this review, we outline the current understanding of PKC signaling "in" and "to" the nucleus, with significant focus on established paradigms of PKC-mediated transcriptional control. Dissecting these complexities would allow the identification of relevant molecular targets implicated in a wide spectrum of diseases.
Collapse
Affiliation(s)
- Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| |
Collapse
|
5
|
Turkmen AM, Saik NO, Ullman KS. The dynamic nuclear envelope: resilience in health and dysfunction in disease. Curr Opin Cell Biol 2023; 85:102230. [PMID: 37660480 PMCID: PMC10843620 DOI: 10.1016/j.ceb.2023.102230] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023]
Abstract
The canonical appearance of the nucleus depends on constant adaptation and remodeling of the nuclear envelope in response to changing biomechanical forces and metabolic demands. Dynamic events at the nuclear envelope play a vital role in supporting key nuclear functions as well as conferring plasticity to this organelle. Moreover, imbalance of these dynamic processes is emerging as a central feature of disease etiology. This review focuses on recent advances that shed light on the myriad events at the nuclear envelope that contribute to resilience and flexibility in nuclear architecture.
Collapse
Affiliation(s)
- Ayse M Turkmen
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Natasha O Saik
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA.
| |
Collapse
|
6
|
Lee S, Carrasquillo Rodríguez JW, Merta H, Bahmanyar S. A membrane-sensing mechanism links lipid metabolism to protein degradation at the nuclear envelope. J Cell Biol 2023; 222:e202304026. [PMID: 37382667 PMCID: PMC10309186 DOI: 10.1083/jcb.202304026] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/22/2023] [Accepted: 06/02/2023] [Indexed: 06/30/2023] Open
Abstract
Lipid composition determines organelle identity; however, whether the lipid composition of the inner nuclear membrane (INM) domain of the ER contributes to its identity is not known. Here, we show that the INM lipid environment of animal cells is under local control by CTDNEP1, the master regulator of the phosphatidic acid phosphatase lipin 1. Loss of CTDNEP1 reduces association of an INM-specific diacylglycerol (DAG) biosensor and results in a decreased percentage of polyunsaturated containing DAG species. Alterations in DAG metabolism impact the levels of the resident INM protein Sun2, which is under local proteasomal regulation. We identify a lipid-binding amphipathic helix (AH) in the nucleoplasmic domain of Sun2 that prefers membrane packing defects. INM dissociation of the Sun2 AH is linked to its proteasomal degradation. We suggest that direct lipid-protein interactions contribute to sculpting the INM proteome and that INM identity is adaptable to lipid metabolism, which has broad implications on disease mechanisms associated with the nuclear envelope.
Collapse
Affiliation(s)
- Shoken Lee
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | | | - Holly Merta
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Shirin Bahmanyar
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| |
Collapse
|
7
|
Saik NO, Ptak C, Rehman S, Aitchison JD, Montpetit B, Wozniak RW. SUMOylation at the inner nuclear membrane facilitates nuclear envelope biogenesis during mitosis. J Cell Biol 2023; 222:e202208137. [PMID: 37398994 PMCID: PMC10318406 DOI: 10.1083/jcb.202208137] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 03/24/2023] [Accepted: 05/15/2023] [Indexed: 07/04/2023] Open
Abstract
As eukaryotic cells progress through cell division, the nuclear envelope (NE) membrane must expand to accommodate the formation of progeny nuclei. In Saccharomyces cerevisiae, closed mitosis allows visualization of NE biogenesis during mitosis. During this period, the SUMO E3 ligase Siz2 binds the inner nuclear membrane (INM) and initiates a wave of INM protein SUMOylation. Here, we show these events increase INM levels of phosphatidic acid (PA), an intermediate of phospholipid biogenesis, and are necessary for normal mitotic NE membrane expansion. The increase in INM PA is driven by the Siz2-mediated inhibition of the PA phosphatase Pah1. During mitosis, this results from the binding of Siz2 to the INM and dissociation of Spo7 and Nem1, a complex required for the activation of Pah1. As cells enter interphase, the process is then reversed by the deSUMOylase Ulp1. This work further establishes a central role for temporally controlled INM SUMOylation in coordinating processes, including membrane expansion, that regulate NE biogenesis during mitosis.
Collapse
Affiliation(s)
- Natasha O. Saik
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Saif Rehman
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - John D. Aitchison
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
- Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics and Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Richard W. Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
8
|
Alam S, Gu Y, Reichert P, Bähler J, Oliferenko S. Optimization of energy production and central carbon metabolism in a non-respiring eukaryote. Curr Biol 2023; 33:2175-2186.e5. [PMID: 37164017 PMCID: PMC7615655 DOI: 10.1016/j.cub.2023.04.046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/30/2023] [Accepted: 04/18/2023] [Indexed: 05/12/2023]
Abstract
Most eukaryotes respire oxygen, using it to generate biomass and energy. However, a few organisms have lost the capacity to respire. Understanding how they manage biomass and energy production may illuminate the critical points at which respiration feeds into central carbon metabolism and explain possible routes to its optimization. Here, we use two related fission yeasts, Schizosaccharomyces pombe and Schizosaccharomyces japonicus, as a comparative model system. We show that although S. japonicus does not respire oxygen, unlike S. pombe, it is capable of efficient NADH oxidation, amino acid synthesis, and ATP generation. We probe possible optimization strategies through the use of stable isotope tracing metabolomics, mass isotopologue distribution analysis, genetics, and physiological experiments. S. japonicus appears to have optimized cytosolic NADH oxidation via glycerol-3-phosphate synthesis. It runs a fully bifurcated TCA pathway, sustaining amino acid production. Finally, we propose that it has optimized glycolysis to maintain high ATP/ADP ratio, in part by using the pentose phosphate pathway as a glycolytic shunt, reducing allosteric inhibition of glycolysis and supporting biomass generation. By comparing two related organisms with vastly different metabolic strategies, our work highlights the versatility and plasticity of central carbon metabolism in eukaryotes, illuminating critical adaptations supporting the preferential use of glycolysis over oxidative phosphorylation.
Collapse
Affiliation(s)
- Sara Alam
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
| | - Ying Gu
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
| | - Polina Reichert
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK; School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Jürg Bähler
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK.
| |
Collapse
|
9
|
First person – Sherman Foo. J Cell Sci 2023. [DOI: 10.1242/jcs.261013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping researchers promote themselves alongside their papers. Sherman Foo is first author on ‘ Diacylglycerol at the inner nuclear membrane fuels nuclear envelope expansion in closed mitosis’, published in JCS. Sherman conducted the research described in this article while a PhD student in the labs of Snezhana Oliferenko (The Francis Crick Institute, London, UK, and Randall Centre for Cell and Molecular Biophysics, King's College London, UK) and Markus R. Wenk (Singapore Lipidomics Incubator, National University of Singapore). He is now a postdoc in the lab of Buzz Baum at Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK, where he is currently studying cellular organization of hyperthermophilic archaea, with a particular focus on the surface layer and cell cycle of Sulfolobus acidocaldarius.
Collapse
|