1
|
Alsina FC, Lupan BM, Lin LJ, Musso CM, Mosti F, Newman CR, Wood LM, Suzuki A, Agostino M, Moore JK, Silver DL. The RNA-binding protein EIF4A3 promotes axon development by direct control of the cytoskeleton. Cell Rep 2024; 43:114666. [PMID: 39182224 DOI: 10.1016/j.celrep.2024.114666] [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: 03/30/2023] [Revised: 02/28/2024] [Accepted: 08/06/2024] [Indexed: 08/27/2024] Open
Abstract
The exon junction complex (EJC), nucleated by EIF4A3, is indispensable for mRNA fate and function throughout eukaryotes. We discover that EIF4A3 directly controls microtubules, independent of RNA, which is critical for neural wiring. While neuronal survival in the developing mouse cerebral cortex depends upon an intact EJC, axonal tract development requires only Eif4a3. Using human cortical organoids, we show that EIF4A3 disease mutations also impair neuronal growth, highlighting conserved functions relevant for neurodevelopmental pathology. Live imaging of growing neurons shows that EIF4A3 is essential for microtubule dynamics. Employing biochemistry and competition experiments, we demonstrate that EIF4A3 directly binds to microtubules, mutually exclusive of the EJC. Finally, in vitro reconstitution assays and rescue experiments demonstrate that EIF4A3 is sufficient to promote microtubule polymerization and that EIF4A3-microtubule association is a major contributor to axon growth. This reveals a fundamental mechanism by which neurons re-utilize core gene expression machinery to directly control the cytoskeleton.
Collapse
Affiliation(s)
- Fernando C Alsina
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Bianca M Lupan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Lydia J Lin
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Camila M Musso
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Federica Mosti
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Carly R Newman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Lisa M Wood
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Aussie Suzuki
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, WI, USA
| | - Mark Agostino
- Curtin Health Innovation Research Institute, Curtin Medical School, and Curtin Institute for Computation, Curtin University, Bentley, WA 6102, Australia
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Departments of Cell Biology and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences and Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA.
| |
Collapse
|
2
|
Martinez A, Stemm-Wolf AJ, Sheridan RM, Taliaferro MJ, Pearson CG. The Unkempt RNA binding protein reveals a local translation program in centriole overduplication. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.29.605660. [PMID: 39131325 PMCID: PMC11312568 DOI: 10.1101/2024.07.29.605660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Excess centrosomes cause defects in mitosis, cell-signaling, and cell migration, and therefore their assembly is tightly regulated. Plk4 controls centriole duplication at the heart of centrosome assembly, and elevation of Plk4 promotes centrosome amplification (CA), a founding event of tumorigenesis. Here, we investigate the transcriptional consequences of elevated Plk4 and find Unkempt, a gene encoding an RNA binding protein with roles in translational regulation, to be one of only two upregulated mRNAs. Unk protein localizes to centrosomes and Cep131-positive centriolar satellites and is required for Plk4-induced centriole overduplication in an RNA-binding dependent manner. Translation is enriched at centrosomes and centriolar satellites with Unk and Cep131 promoting this localized translation. A transient centrosomal downregulation of translation occurs early in Plk4-induced CA. CNOT9, an Unk interactor and component of the translational inhibitory CCR4-NOT complex, localizes to centrosomes at this time. In summary, centriolar satellites and Unk promote local translation as part of a translational program that ensures centriole duplication.
Collapse
Affiliation(s)
- Abraham Martinez
- Department of Cell and Developmental Biology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045
| | - Alexander J. Stemm-Wolf
- Department of Cell and Developmental Biology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045
| | - Ryan M. Sheridan
- RNA Bioscience Initiative (RBI), University of Colorado, Anschutz Medical Campus, Aurora CO 80045
| | - Matthew J. Taliaferro
- RNA Bioscience Initiative (RBI), University of Colorado, Anschutz Medical Campus, Aurora CO 80045
- Department of Biochemistry and Molecular Genetics, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045
| | - Chad G. Pearson
- Department of Cell and Developmental Biology, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045
| |
Collapse
|
3
|
Lupan BM, Solecki RA, Musso CM, Alsina FC, Silver DL. The exon junction complex component EIF4A3 is essential for mouse and human cortical progenitor mitosis and neurogenesis. Development 2023; 150:dev201619. [PMID: 37139782 PMCID: PMC10233715 DOI: 10.1242/dev.201619] [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: 01/13/2023] [Accepted: 04/24/2023] [Indexed: 05/05/2023]
Abstract
Mutations in components of the exon junction complex (EJC) are associated with neurodevelopment and disease. In particular, reduced levels of the RNA helicase EIF4A3 cause Richieri-Costa-Pereira syndrome (RCPS) and copy number variations are linked to intellectual disability. Consistent with this, Eif4a3 haploinsufficient mice are microcephalic. Altogether, this implicates EIF4A3 in cortical development; however, the underlying mechanisms are poorly understood. Here, we use mouse and human models to demonstrate that EIF4A3 promotes cortical development by controlling progenitor mitosis, cell fate and survival. Eif4a3 haploinsufficiency in mice causes extensive cell death and impairs neurogenesis. Using Eif4a3;p53 compound mice, we show that apoptosis has the most impact on early neurogenesis, while additional p53-independent mechanisms contribute to later stages. Live imaging of mouse and human neural progenitors reveals that Eif4a3 controls mitosis length, which influences progeny fate and viability. These phenotypes are conserved, as cortical organoids derived from RCPS iPSCs exhibit aberrant neurogenesis. Finally, using rescue experiments we show that EIF4A3 controls neuron generation via the EJC. Altogether, our study demonstrates that EIF4A3 mediates neurogenesis by controlling mitosis duration and cell survival, implicating new mechanisms that underlie EJC-mediated disorders.
Collapse
Affiliation(s)
- Bianca M. Lupan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Rachel A. Solecki
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Camila M. Musso
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Fernando C. Alsina
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Debra L. Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
- Departments of Cell Biology and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Duke Institute for Brain Sciences and Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
4
|
Mitra R, Rehman A, Singh KK, Jaganathan BG. Multifaceted roles of MAGOH Proteins. Mol Biol Rep 2023; 50:1931-1941. [PMID: 36396768 DOI: 10.1007/s11033-022-07904-1] [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: 02/05/2022] [Revised: 07/14/2022] [Accepted: 08/31/2022] [Indexed: 11/18/2022]
Abstract
MAGOH and MAGOHB are paralog proteins that can substitute each other in the exon junction complex (EJC). The EJC is formed of core components EIF4A3, RBM8A, and MAGOH/MAGOHB. As a part of the EJC, MAGOH proteins are required for mRNA splicing, export, translation and nonsense-mediated mRNA decay (NMD). MAGOH is also essential for embryonic development and normal cellular functioning. The haploinsufficiency of MAGOH results in disorders such as microcephaly and cancer. The present review discusses the discovery of MAGOH, its paralog MAGOHB, their roles in cellular function as part of the EJC, and other cellular roles that are not directly associated with mRNA processing. We also discuss how MAGOH haploinsufficiency in cancer cells can be exploited to develop a novel targeted cancer treatment.
Collapse
Affiliation(s)
- Rumela Mitra
- Stem Cells and Cancer Biology Research Group, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam, India
| | - Ayushi Rehman
- RNA-Binding Proteins (RBPs) Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam, India
| | - Kusum Kumari Singh
- RNA-Binding Proteins (RBPs) Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam, India.
| | - Bithiah Grace Jaganathan
- Stem Cells and Cancer Biology Research Group, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam, India.
- Jyoti and Bhupat Mehta School of Health Sciences and Technology, Indian Institute of Technology Guwahati, 781039, Guwahati, Assam, India.
| |
Collapse
|
5
|
Lupan BM, Solecki RA, Musso CM, Alsina FC, Silver DL. The exon junction complex component EIF4A3 is essential for mouse and human cortical progenitor mitosis and neurogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.524010. [PMID: 36711736 PMCID: PMC9882224 DOI: 10.1101/2023.01.13.524010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Mutations in components of the exon junction complex (EJC) are associated with neurodevelopment and disease. In particular, reduced levels of the RNA helicase EIF4A3 cause Richieri-Costa-Pereira Syndrome (RCPS) and CNVs are linked to intellectual disability. Consistent with this, Eif4a3 haploinsufficient mice are microcephalic. Altogether, this implicates EIF4A3 in cortical development; however, the underlying mechanisms are poorly understood. Here, we use mouse and human models to demonstrate that EIF4A3 promotes cortical development by controlling progenitor mitosis, cell fate, and survival. Eif4a3 haploinsufficiency in mice causes extensive cell death and impairs neurogenesis. Using Eif4a3 ; p53 compound mice, we show that apoptosis is most impactful for early neurogenesis, while additional p53-independent mechanisms contribute to later stages. Live imaging of mouse and human neural progenitors reveals Eif4a3 controls mitosis length, which influences progeny fate and viability. These phenotypes are conserved as cortical organoids derived from RCPS iPSCs exhibit aberrant neurogenesis. Finally, using rescue experiments we show that EIF4A3 controls neuron generation via the EJC. Altogether, our study demonstrates that EIF4A3 mediates neurogenesis by controlling mitosis duration and cell survival, implicating new mechanisms underlying EJC-mediated disorders. Summary statement This study shows that EIF4A3 mediates neurogenesis by controlling mitosis duration in both mouse and human neural progenitors, implicating new mechanisms underlying neurodevelopmental disorders.
Collapse
|
6
|
Martin H, Rupkey J, Asthana S, Yoon J, Patel S, Mott J, Pei Z, Mao Y. Diverse Roles of the Exon Junction Complex Factors in the Cell Cycle, Cancer, and Neurodevelopmental Disorders-Potential for Therapeutic Targeting. Int J Mol Sci 2022; 23:ijms231810375. [PMID: 36142288 PMCID: PMC9499366 DOI: 10.3390/ijms231810375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 12/04/2022] Open
Abstract
The exon junction complex (EJC) plays a crucial role in regulating gene expression at the levels of alternative splicing, translation, mRNA localization, and nonsense-mediated decay (NMD). The EJC is comprised of three core proteins: RNA-binding motif 8A (RBM8A), Mago homolog (MAGOH), eukaryotic initiation factor 4A3 (eIF4A3), and a peripheral EJC factor, metastatic lymph node 51 (MLN51), in addition to other peripheral factors whose structural integration is activity-dependent. The physiological and mechanistic roles of the EJC in contribution to molecular, cellular, and organismal level function continue to be explored for potential insights into genetic or pathological dysfunction. The EJC’s specific role in the cell cycle and its implications in cancer and neurodevelopmental disorders prompt enhanced investigation of the EJC as a potential target for these diseases. In this review, we highlight the current understanding of the EJC’s position in the cell cycle, its relation to cancer and developmental diseases, and potential avenues for therapeutic targeting.
Collapse
Affiliation(s)
- Hannah Martin
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
| | - Julian Rupkey
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
| | - Shravan Asthana
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
- Feinberg School of Medicine, Northwestern University, 303 East Superior Street, Chicago, IL 60611, USA
| | - Joy Yoon
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
| | - Shray Patel
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
| | - Jennifer Mott
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
| | - Zifei Pei
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
| | - Yingwei Mao
- Department of Biology, Pennsylvania State University, University Park, State College, PA 16802, USA
- Correspondence:
| |
Collapse
|
7
|
Multiple Phosphorylations of SR Protein SRSF3 and Its Binding to m6A Reader YTHDC1 in Human Cells. Cells 2022; 11:cells11091461. [PMID: 35563766 PMCID: PMC9100204 DOI: 10.3390/cells11091461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/04/2022] Open
Abstract
N6-methyladenosine (m6A) is a well-known RNA modification and has various functions with its binding proteins. Nuclear m6A reader protein YTHDC1 plays a significant role in RNA metabolism including some non-coding RNA such as LINE or circRNA. It is also known to regulate mRNA splicing through recruiting SRSF3 to the targeted mRNAs, which then mediates export of YTHDC1-bound RNA to the cytoplasm. Additionally, it has been indicated that SRSF3 binding to YHTDC1 may be mediated by its dephosphorylated status. However, their binding mechanism, including the positions of dephosphorylated residues of SRSF3, has not been sufficiently investigated. Thus, we explored the mechanism of interaction between SRSF3 and YTHDC1 in human cells. We used co-immunoprecipitation to examine the binding of YTHDC1/SRSF3 through their N- and C-terminal amino-acid residues. Furthermore, dephosphorylation-mimic serine to alanine mutants of SRSF3 indicated the position of phosphorylated residues. Cumulatively, our results demonstrate that YTHDC1 binding to SRSF3 is regulated by not only hypo-phosphorylated residues of arginine/serine-rich (RS) domain of SRSF3 but also other parts of SRSF3 via YTHDC1 N- or C-terminal residues. Our results contribute to the understanding of the complex mechanism of binding between SR protein SRSF3 and the m6A reader YTHDC1 to regulate the expression of mRNA and non-coding RNAs.
Collapse
|
8
|
Zein-Sabatto H, Lerit DA. The Identification and Functional Analysis of mRNA Localizing to Centrosomes. Front Cell Dev Biol 2021; 9:782802. [PMID: 34805187 PMCID: PMC8595238 DOI: 10.3389/fcell.2021.782802] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
Centrosomes are multifunctional organelles tasked with organizing the microtubule cytoskeleton required for genome stability, intracellular trafficking, and ciliogenesis. Contributing to the diversity of centrosome functions are cell cycle-dependent oscillations in protein localization and post-translational modifications. Less understood is the role of centrosome-localized messenger RNA (mRNA). Since its discovery, the concept of nucleic acids at the centrosome was controversial, and physiological roles for centrosomal mRNAs remained muddled and underexplored. Over the past decades, however, transcripts, RNA-binding proteins, and ribosomes were detected at the centrosome in various organisms and cell types, hinting at a conservation of function. Indeed, recent work defines centrosomes as sites of local protein synthesis, and defined mRNAs were recently implicated in regulating centrosome functions. In this review, we summarize the evidence for the presence of mRNA at the centrosome and the current work that aims to unravel the biological functions of mRNA localized to centrosomes.
Collapse
Affiliation(s)
| | - Dorothy A. Lerit
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| |
Collapse
|
9
|
Ito KK, Watanabe K, Kitagawa D. The Emerging Role of ncRNAs and RNA-Binding Proteins in Mitotic Apparatus Formation. Noncoding RNA 2020; 6:E13. [PMID: 32245090 PMCID: PMC7151635 DOI: 10.3390/ncrna6010013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 12/14/2022] Open
Abstract
Mounting experimental evidence shows that non-coding RNAs (ncRNAs) serve a wide variety of biological functions. Recent studies suggest that a part of ncRNAs are critically important for supporting the structure of subcellular architectures. Here, we summarize the current literature demonstrating the role of ncRNAs and RNA-binding proteins in regulating the assembly of mitotic apparatus, especially focusing on centrosomes, kinetochores, and mitotic spindles.
Collapse
Affiliation(s)
| | | | - Daiju Kitagawa
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan; (K.K.I.); (K.W.)
| |
Collapse
|
10
|
Ma Q, Tatsuno T, Nakamura Y, Izumi S, Tomosugi N, Ishigaki Y. Immuno‐detection of mRNA‐binding protein complex in human cells under transmission electron microscopy. Microsc Res Tech 2019; 82:680-688. [DOI: 10.1002/jemt.23214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 12/13/2018] [Accepted: 12/15/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Qingfeng Ma
- Medical Research InstituteKanazawa Medical University Uchinada Kahoku Japan
- Department of Clinical Laboratory, Liyuan Hospital, Tongji Medical CollegeHuazhong University of Science and Technology Wuhan China
| | - Takanori Tatsuno
- Medical Research InstituteKanazawa Medical University Uchinada Kahoku Japan
| | - Yuka Nakamura
- Medical Research InstituteKanazawa Medical University Uchinada Kahoku Japan
| | - Shin‐Ichi Izumi
- Department of Cell Biology, Unit of Biomedical SciencesNagasaki University Graduate School of Biomedical Sciences Sakamoto Nagasaki Japan
| | - Naohisa Tomosugi
- Medical Research InstituteKanazawa Medical University Uchinada Kahoku Japan
- Medical Care Proteomics Biotechnology Co., Ltd. Uchinada Kahoku Japan
| | - Yasuhito Ishigaki
- Medical Research InstituteKanazawa Medical University Uchinada Kahoku Japan
| |
Collapse
|
11
|
C-terminal short arginine/serine repeat sequence-dependent regulation of Y14 (RBM8A) localization. Sci Rep 2018; 8:612. [PMID: 29330450 PMCID: PMC5766523 DOI: 10.1038/s41598-017-18765-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/15/2017] [Indexed: 01/01/2023] Open
Abstract
Y14 (RBM8A) is an RNA recognition motif-containing protein that forms heterodimers with MAGOH and serves as a core factor of the RNA surveillance machinery for the exon junction complex (EJC). The role of the Y14 C-terminal serine/arginine (RS) repeat-containing region, which has been reported to undergo modifications such as phosphorylation and methylation, has not been sufficiently investigated. Thus, we aimed to explore the functional significance of the Y14 C-terminal region. Deletion or dephosphorylation mimic mutants of the C-terminal region showed a shift in localization from the nucleoplasmic region; in addition, the C-terminal RS repeat-containing sequence itself exhibited the potential for nucleolar localization. Additionally, the regulation of Y14 localization by the C-terminal region was further found to be exquisitely controlled by MAGOH binding. Cumulatively, our findings, which demonstrated that Y14 localization is regulated not only by the previously reported N-terminal localization signal but also by the C-terminal RS repeat-containing region through phosphorylation and MAGOH binding to Y14, provide new insights for the mechanism of localization of short RS repeat-containing proteins.
Collapse
|
12
|
Lu CC, Lee CC, Tseng CT, Tarn WY. Y14 governs p53 expression and modulates DNA damage sensitivity. Sci Rep 2017; 7:45558. [PMID: 28361991 PMCID: PMC5374521 DOI: 10.1038/srep45558] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/27/2017] [Indexed: 01/29/2023] Open
Abstract
Y14 is a core component of the exon junction complex (EJC), while it also exerts cellular functions independent of the EJC. Depletion of Y14 causes G2/M arrest, DNA damage and apoptosis. Here we show that knockdown of Y14 induces the expression of an alternative spliced isoform of p53, namely p53β, in human cells. Y14, in the context of the EJC, inhibited aberrant exon inclusion during the splicing of p53 pre-mRNA, and thus prevent p53β expression. The anti-cancer agent camptothecin specifically suppressed p53β induction. Intriguingly, both depletion and overexpression of Y14 increased overall p53 protein levels, suggesting that Y14 governs the quality and quantity control of p53. Moreover, Y14 depletion unexpectedly reduced p21 protein levels, which in conjunction with aberrant p53 expression accordingly increased cell sensitivity to genotoxic agents. This study establishes a direct link between Y14 and p53 expression and suggests a function for Y14 in DNA damage signaling.
Collapse
Affiliation(s)
- Chia-Chen Lu
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chi-Chieh Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ching-Tzu Tseng
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Woan-Yuh Tarn
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
13
|
Liang R, Lin Y, Ye JZ, Yan XX, Liu ZH, Li YQ, Luo XL, Ye HH. High expression of RBM8A predicts poor patient prognosis and promotes tumor progression in hepatocellular carcinoma. Oncol Rep 2017; 37:2167-2176. [PMID: 28259942 DOI: 10.3892/or.2017.5457] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/30/2017] [Indexed: 11/06/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a huge threat for human health worldwide. As a complicated tumor, the molecular basis for HCC development especially metastasis requires exploration. Although RNA binding motif (RBM) proteins are closely related to various cancers, the clinical importance and underlying mechanisms of RBM8A in HCC remain elusive. In this study, we found that RBM8A was highly expressed in HCC tumor tissues compared to normal liver tissues. Overexpression of RBM8A was associated with HbsAg and Edmondson pathological grading. Moreover, Kaplan-Meier survival analysis showed that high expression of RBM8A was related to the poor overall survival and progression-free survival of patients with HCC. Gain- and loss-of-function experiments further demonstrated that RBM8A promoted tumor cell migration and invasion in HCC via activation of epithelial-mesenchymal transition signaling pathway. It is also noteworthy that RBM8A is required for tumor cell proliferation and anti-apoptosis in HCC. Altogether, our results revealed a close relationship between RBM8A and HCC prognosis as well as a critical tumor-promoting function of RBM8A in HCC progression, suggesting that RBM8A might be a potential bio-marker and drug target in HCC therapy.
Collapse
Affiliation(s)
- Rong Liang
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Yan Lin
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Jia-Zhou Ye
- Department of Hepatobilliary Surgery, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 530022, P.R. China
| | - Xue-Xin Yan
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Zhi-Hui Liu
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Yong-Qiang Li
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Xiao-Ling Luo
- First Department of Chemotherapy, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi 5300221, P.R. China
| | - Hai-Hong Ye
- Department of Hepatobilliary Surgery, Affiliated Minzu Hospital of Guangxi Medical University, Nanning, Guangxi 530001, P.R. China
| |
Collapse
|
14
|
Stubenvoll MD, Medley JC, Irwin M, Song MH. ATX-2, the C. elegans Ortholog of Human Ataxin-2, Regulates Centrosome Size and Microtubule Dynamics. PLoS Genet 2016; 12:e1006370. [PMID: 27689799 PMCID: PMC5045193 DOI: 10.1371/journal.pgen.1006370] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/16/2016] [Indexed: 11/26/2022] Open
Abstract
Centrosomes are critical sites for orchestrating microtubule dynamics, and exhibit dynamic changes in size during the cell cycle. As cells progress to mitosis, centrosomes recruit more microtubules (MT) to form mitotic bipolar spindles that ensure proper chromosome segregation. We report a new role for ATX-2, a C. elegans ortholog of Human Ataxin-2, in regulating centrosome size and MT dynamics. ATX-2, an RNA-binding protein, forms a complex with SZY-20 in an RNA-independent fashion. Depleting ATX-2 results in embryonic lethality and cytokinesis failure, and restores centrosome duplication to zyg-1 mutants. In this pathway, SZY-20 promotes ATX-2 abundance, which inversely correlates with centrosome size. Centrosomes depleted of ATX-2 exhibit elevated levels of centrosome factors (ZYG-1, SPD-5, γ-Tubulin), increasing MT nucleating activity but impeding MT growth. We show that ATX-2 influences MT behavior through γ-Tubulin at the centrosome. Our data suggest that RNA-binding proteins play an active role in controlling MT dynamics and provide insight into the control of proper centrosome size and MT dynamics. The microtubule (MT) cytoskeleton undergoes dynamic rearrangements during the cell cycle. As the primary microtubule-organizing center, centrosomes orchestrate MT dynamics and play a key role in establishing bipolar spindles in mitosis. Errors in centrosome assembly lead to missegregation of genomic content and aneuploidy. Thus, stringent regulation of centrosome assembly is of vital importance for the fidelity of cell division and survival. Using the nematode Caenorhabditis elegans (C. elegans) as a model, we study the role of the RNA-binding protein, ATX-2, a C. elegans homolog of Human Ataxin-2 in early cell division. A number of RNAs and RNA-binding proteins are shown to be associated with centrosomes and MTs, and influence the assembly of mitotic spindles. In C. elegans, the RNA-binding role of SZY-20 is implicated in regulating centrosome size. We show that ATX-2 functions together with SZY-20 in centrosome size and MT behavior. SZY-20 promotes ATX-2 protein levels, and the amount of ATX-2 influences centrosome size and subsequent MT dynamics. Our work provides evidence that RNA-binding proteins have an active role in controlling MT dynamics.
Collapse
Affiliation(s)
- Michael D. Stubenvoll
- Department of Biological Sciences, Oakland University, Rochester, Michigan, United States of America
| | - Jeffrey C. Medley
- Department of Biological Sciences, Oakland University, Rochester, Michigan, United States of America
| | - Miranda Irwin
- Department of Biological Sciences, Oakland University, Rochester, Michigan, United States of America
| | - Mi Hye Song
- Department of Biological Sciences, Oakland University, Rochester, Michigan, United States of America
- * E-mail:
| |
Collapse
|
15
|
Pilaz LJ, McMahon JJ, Miller EE, Lennox AL, Suzuki A, Salmon E, Silver DL. Prolonged Mitosis of Neural Progenitors Alters Cell Fate in the Developing Brain. Neuron 2016; 89:83-99. [PMID: 26748089 DOI: 10.1016/j.neuron.2015.12.007] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 09/27/2015] [Accepted: 11/24/2015] [Indexed: 12/14/2022]
Abstract
Embryonic neocortical development depends on balanced production of progenitors and neurons. Genetic mutations disrupting progenitor mitosis frequently impair neurogenesis; however, the link between altered mitosis and cell fate remains poorly understood. Here we demonstrate that prolonged mitosis of radial glial progenitors directly alters neuronal fate specification and progeny viability. Live imaging of progenitors from a neurogenesis mutant, Magoh(+/-), reveals that mitotic delay significantly correlates with preferential production of neurons instead of progenitors, as well as apoptotic progeny. Independently, two pharmacological approaches reveal a causal relationship between mitotic delay and progeny fate. As mitotic duration increases, progenitors produce substantially more apoptotic progeny or neurons. We show that apoptosis, but not differentiation, is p53 dependent, demonstrating that these are distinct outcomes of mitotic delay. Together our findings reveal that prolonged mitosis is sufficient to alter fates of radial glia progeny and define a new paradigm to understand how mitosis perturbations underlie brain size disorders such as microcephaly.
Collapse
Affiliation(s)
- Louis-Jan Pilaz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - John J McMahon
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Emily E Miller
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ashley L Lennox
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Aussie Suzuki
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Edward Salmon
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA.
| |
Collapse
|
16
|
Tatsuno T, Nakamura Y, Ma S, Tomosugi N, Ishigaki Y. Nonsense-mediated mRNA decay factor Upf2 exists in both the nucleoplasm and the cytoplasm. Mol Med Rep 2016; 14:655-60. [PMID: 27221324 PMCID: PMC4918542 DOI: 10.3892/mmr.2016.5331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 04/20/2016] [Indexed: 11/24/2022] Open
Abstract
Upf2 protein predominantly localizes to the cytoplasmic fraction, and binds to the exon junction complex (EJC) on spliced mRNA. The present study aimed to determine the cellular site where the interaction between Upf2 and EJC occurs. First, the cell lysate was fractionated into the cytoplasm and nucleoplasm, and western blotting to detect levels of Upf2 protein was performed. Upf2 was clearly detected in the cytoplasm and in the nucleoplasm. Secondly, immunostaining was performed, and the majority of Upf2 was detected in the cytoplasmic perinuclear region; a small quantity of Upf2 was detected in the intranuclear region. RNase treatment of the cells reduced the Upf2 immunostained signal. The immune-purified fractions containing nuclear and cytoplasmic Upf2 also contained one of the EJC core factors, RBM8A. These results implied the existence of Upf2 in the nucleoplasm and the cytoplasm, and it appeared to be involved in the construction of the mRNA complex. In order to verify the construction of Upf2-binding EJC in the nucleoplasm, an in situ proximity ligation assay was performed with anti-Upf2 and anti-RBM8A antibodies. These results demonstrated that their interaction occurred not only in the cytoplasmic region, but also in the intranuclear region. Taken together, these results suggested that Upf2 combines with EJC in both the cytoplasmic and the intranuclear fractions, and that it is involved in mRNA metabolism in human cells.
Collapse
Affiliation(s)
- Takanori Tatsuno
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
| | - Yuka Nakamura
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
| | - Shaofu Ma
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
| | - Naohisa Tomosugi
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
| | - Yasuhito Ishigaki
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920‑0293, Japan
| |
Collapse
|
17
|
Chuang TW, Lee KM, Tarn WY. Function and pathological implications of exon junction complex factor Y14. Biomolecules 2015; 5:343-55. [PMID: 25866920 PMCID: PMC4496676 DOI: 10.3390/biom5020343] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 01/01/2023] Open
Abstract
Eukaryotic mRNA biogenesis involves a series of interconnected steps, including nuclear pre-mRNA processing, mRNA export, and surveillance. The exon-junction complex (EJC) is deposited on newly spliced mRNAs and coordinates several downstream steps of mRNA biogenesis. The EJC core protein, Y14, functions with its partners in nonsense-mediated mRNA decay and translational enhancement. Y14 plays additional roles in mRNA metabolism, some of which are independent of the EJC, and it is also involved in other cellular processes. Genetic mutations or aberrant expression of Y14 results in physiological abnormality and may cause disease. Therefore, it is important to understand the various functions of Y14 and its physiological and pathological roles.
Collapse
Affiliation(s)
- Tzu-Wei Chuang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
| | - Kou-Ming Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
| |
Collapse
|
18
|
The Histochemistry and Cell Biology pandect: the year 2014 in review. Histochem Cell Biol 2015; 143:339-68. [PMID: 25744491 DOI: 10.1007/s00418-015-1313-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2015] [Indexed: 02/07/2023]
Abstract
This review encompasses a brief synopsis of the articles published in 2014 in Histochemistry and Cell Biology. Out of the total of 12 issues published in 2014, two special issues were devoted to "Single-Molecule Super-Resolution Microscopy." The present review is divided into 11 categories, providing an easy format for readers to quickly peruse topics of particular interest to them.
Collapse
|
19
|
Nakamura Y, Ishigaki Y. Immunostaining and time-lapse analysis of vinblastine-induced paracrystal formation in human A549 cells. Oncol Lett 2014; 8:2387-2392. [PMID: 25364400 PMCID: PMC4214480 DOI: 10.3892/ol.2014.2549] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 08/01/2014] [Indexed: 11/05/2022] Open
Abstract
Vinblastine is a vinca alkaloid that binds to tubulin and inhibits microtubule formation in cells. Vinblastine treatment results in the formation of paracrystalline aggregates in the cells, which are formed from tightly packed tubulin molecules. Mitotic spindle assemblies in treated cells are disrupted and cell cycle progression is arrested at the mitosis phase. Vinblastine is therefore widely used for cancer treatment. However, the mechanism underlying paracrystal formation has not been fully elucidated. The present study attempted to observe paracrystal formation in human A549 cells. Initally, paracrystal formation was detected using the anti-tubulin antibody. Secondly, the exogenousuly expressed RFP-conjugated tubulin also formed paracrystals. Additionally, immunostaining with the anti-RBM8A antibody overlapped with paracrystal images obtained from RFP conjugated tubulin. This suggested that the localization of the RBM8A proteins was adjacent to the tubulin molecules prior to vinblastine treatment. Furthermore, a time-lapse analysis was developed for paracrystal formation in viable human A549 cells. This was achieved using exogenous expression of fluorescent proteins conjugated with tubulin and time-lapse microscopy. It may be concluded that the indicated method was successful for the real-time analysis of paracrystal formation in human cells.
Collapse
Affiliation(s)
- Yuka Nakamura
- Medical Research Institute, Kanazawa Medical University, Ishikawa 920-0293, Japan
| | - Yasuhito Ishigaki
- Medical Research Institute, Kanazawa Medical University, Ishikawa 920-0293, Japan
| |
Collapse
|
20
|
Ishigaki Y, Nakamura Y, Tatsuno T, Ma S, Tomosugi N. Phosphorylation status of human RNA-binding protein 8A in cells and its inhibitory regulation by Magoh. Exp Biol Med (Maywood) 2014; 240:438-45. [PMID: 25349214 DOI: 10.1177/1535370214556945] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 09/11/2014] [Indexed: 11/17/2022] Open
Abstract
The RNA-binding protein 8A (RBM8A)-mago-nashi homolog, proliferation-associated (Magoh) complex is a component of the exon junction complex (EJC) required for mRNA metabolism involving nonsense-mediated mRNA decay (NMD). RBM8A is a phosphorylated protein that plays some roles in NMD. However, the detailed status and mechanism of the phosphorylation of RBM8A is not completely understood. Therefore, in this study, we analyzed in detail RBM8A phosphorylation in human cells. Accordingly, analysis of the phosphorylation status of RBM8A protein in whole-cell lysates by using Phos-tag gels revealed that the majority of endogenous RBM8A was phosphorylated throughout the cell-cycle progression. Nuclear and cytoplasmic RBM8A and RBM8A in the EJC were also found to be mostly phosphorylated. We also screened the phosphorylated serine by mutational analysis using Phos-tag gels to reveal modifications of serine residues 166 and 168. A single substitution at position 168 that concomitantly abolished the phosphorylation of serine 166 suggested the priority of kinase reaction between these sites. Furthermore, analysis of the role of the binding protein Magoh in RBM8A phosphorylation revealed its inhibitory effect in vitro and in vivo. Thus, we conclude that almost all synthesized RBM8A proteins are rapidly phosphorylated in cells and that phosphorylation occurs before the complex formation with Magoh.
Collapse
Affiliation(s)
- Yasuhito Ishigaki
- Medical Research Institute, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-0293, Japan
| | - Yuka Nakamura
- Medical Research Institute, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-0293, Japan
| | - Takanori Tatsuno
- Medical Research Institute, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-0293, Japan
| | - Shaofu Ma
- Medical Research Institute, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-0293, Japan
| | - Naohisa Tomosugi
- Medical Research Institute, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-0293, Japan Medical Care Proteomics Biotechnology Co., Ltd., Uchinada-machi, Kahoku 920-0293, Japan
| |
Collapse
|
21
|
Amato R, Morleo M, Giaquinto L, di Bernardo D, Franco B. A network-based approach to dissect the cilia/centrosome complex interactome. BMC Genomics 2014; 15:658. [PMID: 25102769 PMCID: PMC4137083 DOI: 10.1186/1471-2164-15-658] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/31/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cilia are microtubule-based organelles protruding from almost all mammalian cells which, when dysfunctional, result in genetic disorders called "ciliopathies". High-throughput studies have revealed that cilia are composed of thousands of proteins. However, despite many efforts, much remains to be determined regarding the biological functions of this increasingly important complex organelle. RESULTS We have derived an online tool, from a systematic network-based approach to dissect the cilia/centrosome complex interactome (CCCI). The tool integrates all current available data into a model which provides an "interaction" perspective on ciliary function. We generated a network of interactions between human proteins organized into functionally relevant "communities", which can be defined as groups of genes that are both highly inter-connected and strongly co-expressed. We then combined sequence and co-expression data in order to identify the transcription factors responsible for regulating genes within their respective communities. Our analyses have discovered communities significantly specialized for delegating specific biological functions such as mRNA processing, protein translation, folding and degradation processes that had never been associated with ciliary proteins until now. CONCLUSIONS CCCI will allow us to clarify the roles of previously unknown ciliary functions, elucidate the molecular mechanisms underlying ciliary-associated phenotypes, and apply our knowledge of the functional roles of relatively uncharacterized molecular entities to disease phenotypes and new clinical applications.
Collapse
Affiliation(s)
| | | | | | | | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy.
| |
Collapse
|