1
|
Ashour K, Sali S, Aldoukhi AH, Hall D, Mubaid S, Busque S, Lian XJ, Gagné JP, Khattak S, Di Marco S, Poirier GG, Gallouzi IE. pADP-ribosylation regulates the cytoplasmic localization, cleavage, and pro-apoptotic function of HuR. Life Sci Alliance 2024; 7:e202302316. [PMID: 38538092 PMCID: PMC10972696 DOI: 10.26508/lsa.202302316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/05/2024] Open
Abstract
HuR (ElavL1) is one of the main post-transcriptional regulators that determines cell fate. Although the role of HuR in apoptosis is well established, the post-translational modifications that govern this function remain elusive. In this study, we show that PARP1/2-mediated poly(ADP)-ribosylation (PARylation) is instrumental in the pro-apoptotic function of HuR. During apoptosis, a substantial reduction in HuR PARylation is observed. This results in the cytoplasmic accumulation and the cleavage of HuR, both of which are essential events for apoptosis. These effects are mediated by a pADP-ribose-binding motif within the HuR-HNS region (HuR PAR-binding site). Under normal conditions, the association of the HuR PAR-binding site with pADP-ribose is responsible for the nuclear retention of HuR. Mutations within this motif prevent the binding of HuR to its import factor TRN2, leading to its cytoplasmic accumulation and cleavage. Collectively, our findings underscore the role of PARylation in controlling the pro-apoptotic function of HuR, offering insight into the mechanism by which PARP1/2 enzymes regulate cell fate and adaptation to various assaults.
Collapse
Affiliation(s)
- Kholoud Ashour
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
- Faculty of Applied Medical Sciences, Medical Laboratory Technology, Taibah University, Medina, Saudi Arabia
| | - Sujitha Sali
- https://ror.org/01q3tbs38 KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Ali H Aldoukhi
- https://ror.org/01q3tbs38 KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Derek Hall
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Souad Mubaid
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Sandrine Busque
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Xian Jin Lian
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Jean-Philippe Gagné
- Centre de recherche du CHU de Québec-Pavillon CHUL, Faculté de Médecine, Université Laval, Québec, Canada
| | - Shahryar Khattak
- https://ror.org/01q3tbs38 KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Sergio Di Marco
- https://ror.org/01q3tbs38 KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
| | - Guy G Poirier
- Centre de recherche du CHU de Québec-Pavillon CHUL, Faculté de Médecine, Université Laval, Québec, Canada
| | - Imed-Eddine Gallouzi
- https://ror.org/01q3tbs38 KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
- Department of Biochemistry, McGill University, Montreal, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Canada
| |
Collapse
|
2
|
Mubaid S, Sanchez BJ, Algehani RA, Skopenkova V, Adjibade P, Hall DT, Busque S, Lian XJ, Ashour K, Tremblay AMK, Carlile G, Gagné JP, Diaz-Gaxiola A, Khattak S, Di Marco S, Thomas DY, Poirier GG, Gallouzi IE. Tankyrase-1 regulates RBP-mediated mRNA turnover to promote muscle fiber formation. Nucleic Acids Res 2024; 52:4002-4020. [PMID: 38321934 DOI: 10.1093/nar/gkae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/19/2024] [Indexed: 02/08/2024] Open
Abstract
Poly(ADP-ribosylation) (PARylation) is a post-translational modification mediated by a subset of ADP-ribosyl transferases (ARTs). Although PARylation-inhibition based therapies are considered as an avenue to combat debilitating diseases such as cancer and myopathies, the role of this modification in physiological processes such as cell differentiation remains unclear. Here, we show that Tankyrase1 (TNKS1), a PARylating ART, plays a major role in myogenesis, a vital process known to drive muscle fiber formation and regeneration. Although all bona fide PARPs are expressed in muscle cells, experiments using siRNA-mediated knockdown or pharmacological inhibition show that TNKS1 is the enzyme responsible of catalyzing PARylation during myogenesis. Via this activity, TNKS1 controls the turnover of mRNAs encoding myogenic regulatory factors such as nucleophosmin (NPM) and myogenin. TNKS1 mediates these effects by targeting RNA-binding proteins such as Human Antigen R (HuR). HuR harbors a conserved TNKS-binding motif (TBM), the mutation of which not only prevents the association of HuR with TNKS1 and its PARylation, but also precludes HuR from regulating the turnover of NPM and myogenin mRNAs as well as from promoting myogenesis. Therefore, our data uncover a new role for TNKS1 as a key modulator of RBP-mediated post-transcriptional events required for vital processes such as myogenesis.
Collapse
Affiliation(s)
- Souad Mubaid
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Brenda Janice Sanchez
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Rinad A Algehani
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Viktoriia Skopenkova
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Pauline Adjibade
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Derek T Hall
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Sandrine Busque
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Xian Jin Lian
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Kholoud Ashour
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Anne-Marie K Tremblay
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - Graeme Carlile
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
| | - Jean-Philippe Gagné
- Centre de recherche du CHU de Québec-Pavillon CHUL, Faculté de Médecine, Université Laval, Québec G1V 4G2, Canada
| | - Andrea Diaz-Gaxiola
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Shahryar Khattak
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Sergio Di Marco
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| | - David Y Thomas
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
| | - Guy G Poirier
- Centre de recherche du CHU de Québec-Pavillon CHUL, Faculté de Médecine, Université Laval, Québec G1V 4G2, Canada
| | - Imed-Eddine Gallouzi
- KAUST Smart-Health Initiative (KSHI) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A 1A3, Canada
| |
Collapse
|
3
|
Peng F, Nordgren CE, Murray JI. A spatiotemporally resolved atlas of mRNA decay in the C. elegans embryo reveals differential regulation of mRNA stability across stages and cell types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575757. [PMID: 38293118 PMCID: PMC10827189 DOI: 10.1101/2024.01.15.575757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
During embryonic development, cells undergo dynamic changes in gene expression that are required for appropriate cell fate specification. Although both transcription and mRNA degradation contribute to gene expression dynamics, patterns of mRNA decay are less well-understood. Here we directly measured spatiotemporally resolved mRNA decay rates transcriptome-wide throughout C. elegans embryogenesis by transcription inhibition followed by bulk and single-cell RNA-sequencing. This allowed us to calculate mRNA half-lives within specific cell types and developmental stages and identify differentially regulated mRNA decay throughout embryonic development. We identified transcript features that are correlated with mRNA stability and found that mRNA decay rates are associated with distinct peaks in gene expression over time. Moreover, we provide evidence that, on average, mRNA is more stable in the germline compared to in the soma and in later embryonic stages compared to in earlier stages. This work suggests that differential mRNA decay across cell states and time helps to shape developmental gene expression, and it provides a valuable resource for studies of mRNA turnover regulatory mechanisms.
Collapse
Affiliation(s)
- Felicia Peng
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - C Erik Nordgren
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
4
|
Sun Y, Zhan S, Zhao S, Zhong T, Wang L, Guo J, Dai D, Li D, Cao J, Li L, Zhang H. HuR Promotes the Differentiation of Goat Skeletal Muscle Satellite Cells by Regulating Myomaker mRNA Stability. Int J Mol Sci 2023; 24:ijms24086893. [PMID: 37108057 PMCID: PMC10138435 DOI: 10.3390/ijms24086893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/29/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Human antigen R (HuR) is an RNA-binding protein that contributes to a wide variety of biological processes and diseases. HuR has been demonstrated to regulate muscle growth and development, but its regulatory mechanisms are not well understood, especially in goats. In this study, we found that HuR was highly expressed in the skeletal muscle of goats, and its expression levels changed during longissimus dorsi muscle development in goats. The effects of HuR on goat skeletal muscle development were explored using skeletal muscle satellite cells (MuSCs) as a model. The overexpression of HuR accelerated the expression of myogenic differentiation 1 (MyoD), Myogenin (MyoG), myosin heavy chain (MyHC), and the formation of myotubes, while the knockdown of HuR showed opposite effects in MuSCs. In addition, the inhibition of HuR expression significantly reduced the mRNA stability of MyoD and MyoG. To determine the downstream genes affected by HuR at the differentiation stage, we conducted RNA-Seq using MuSCs treated with small interfering RNA, targeting HuR. The RNA-Seq screened 31 upregulated and 113 downregulated differentially expressed genes (DEGs) in which 11 DEGs related to muscle differentiation were screened for quantitative real-time PCR (qRT-PCR) detection. Compared to the control group, the expression of three DEGs (Myomaker, CHRNA1, and CAPN6) was significantly reduced in the siRNA-HuR group (p < 0.01). In this mechanism, HuR bound to Myomaker and increased the mRNA stability of Myomaker. It then positively regulated the expression of Myomaker. Moreover, the rescue experiments indicated that the overexpression of HuR may reverse the inhibitory impact of Myomaker on myoblast differentiation. Together, our findings reveal a novel role for HuR in promoting muscle differentiation in goats by increasing the stability of Myomaker mRNA.
Collapse
Affiliation(s)
- Yanjin Sun
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Siyuan Zhan
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Sen Zhao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Tao Zhong
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Linjie Wang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Jiazhong Guo
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| | - Dinghui Dai
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Dandan Li
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Jiaxue Cao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Li Li
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
| | - Hongping Zhang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu 611130, China
| |
Collapse
|
5
|
Sánchez BJ, Mubaid S, Busque S, de los Santos Y, Ashour K, Sadek J, Lian X, Khattak S, Di Marco S, Gallouzi IE. The formation of HuR/YB1 complex is required for the stabilization of target mRNA to promote myogenesis. Nucleic Acids Res 2023; 51:1375-1392. [PMID: 36629268 PMCID: PMC9943665 DOI: 10.1093/nar/gkac1245] [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: 11/24/2022] [Accepted: 12/14/2022] [Indexed: 01/12/2023] Open
Abstract
mRNA stability is the mechanism by which cells protect transcripts allowing their expression to execute various functions that affect cell metabolism and fate. It is well-established that RNA binding proteins (RBPs) such as HuR use their ability to stabilize mRNA targets to modulate vital processes such as muscle fiber formation (myogenesis). However, the machinery and the mechanisms regulating mRNA stabilization are still elusive. Here, we identified Y-Box binding protein 1 (YB1) as an indispensable HuR binding partner for mRNA stabilization and promotion of myogenesis. Both HuR and YB1 bind to 409 common mRNA targets, 147 of which contain a U-rich consensus motif in their 3' untranslated region (3'UTR) that can also be found in mRNA targets in other cell systems. YB1 and HuR form a heterodimer that associates with the U-rich consensus motif to stabilize key promyogenic mRNAs. The formation of this complex involves a small domain in HuR (227-234) that if mutated prevents HuR from reestablishing myogenesis in siHuR-treated muscle cells. Together our data uncover that YB1 is a key player in HuR-mediated stabilization of pro-myogenic mRNAs and provide the first indication that the mRNA stability mechanism is as complex as other key cellular processes such as mRNA decay and translation.
Collapse
Affiliation(s)
- Brenda Janice Sánchez
- KAUST Smart-Health Initiative King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia,KAUST Biological Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia,Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | - Souad Mubaid
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | - Sandrine Busque
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | - Yossef Lopez de los Santos
- KAUST Biological Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Kholoud Ashour
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | - Jason Sadek
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | - Xian Jin Lian
- Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | - Shahryar Khattak
- KAUST Smart-Health Initiative King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia,KAUST Biological Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia
| | - Sergio Di Marco
- KAUST Smart-Health Initiative King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia,KAUST Biological Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Jeddah, Saudi Arabia,Dept. of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G1Y6, Canada,Rosalind & Morris Goodman Cancer Institute, McGill University, 1160 Pine Avenue, Montreal, QC H3A1A3, Canada
| | | |
Collapse
|
6
|
Porpiglia E, Mai T, Kraft P, Holbrook CA, de Morree A, Gonzalez VD, Hilgendorf KI, Frésard L, Trejo A, Bhimaraju S, Jackson PK, Fantl WJ, Blau HM. Elevated CD47 is a hallmark of dysfunctional aged muscle stem cells that can be targeted to augment regeneration. Cell Stem Cell 2022; 29:1653-1668.e8. [PMID: 36384141 PMCID: PMC9746883 DOI: 10.1016/j.stem.2022.10.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 09/04/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022]
Abstract
In aging, skeletal muscle strength and regenerative capacity decline, due in part to functional impairment of muscle stem cells (MuSCs), yet the underlying mechanisms remain elusive. Here, we capitalize on mass cytometry to identify high CD47 expression as a hallmark of dysfunctional MuSCs (CD47hi) with impaired regenerative capacity that predominate with aging. The prevalent CD47hi MuSC subset suppresses the residual functional CD47lo MuSC subset through a paracrine signaling loop, leading to impaired proliferation. We uncover that elevated CD47 levels on aged MuSCs result from increased U1 snRNA expression, which disrupts alternative polyadenylation. The deficit in aged MuSC function in regeneration can be overcome either by morpholino-mediated blockade of CD47 alternative polyadenylation or antibody blockade of thrombospondin-1/CD47 signaling, leading to improved regeneration in aged mice, with therapeutic implications. Our findings highlight a previously unrecognized age-dependent alteration in CD47 levels and function in MuSCs, which underlies reduced muscle repair in aging.
Collapse
Affiliation(s)
- Ermelinda Porpiglia
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Biomedicine, Aarhus University, Aarhus C 8000, Denmark.
| | - Thach Mai
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peggy Kraft
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Colin A Holbrook
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Antoine de Morree
- Department of Biomedicine, Aarhus University, Aarhus C 8000, Denmark; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Veronica D Gonzalez
- Nolan Laboratory, Department of Pathology, Stanford University, Stanford, CA 94305, USA; Department of Urology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Keren I Hilgendorf
- Jackson Laboratory, Baxter Laboratory for Stem Cell Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laure Frésard
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - Angelica Trejo
- Nolan Laboratory, Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - Sriram Bhimaraju
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peter K Jackson
- Jackson Laboratory, Baxter Laboratory for Stem Cell Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wendy J Fantl
- Department of Urology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Helen M Blau
- Baxter Laboratory for Stem Cell Biology, Department of Microbiology and Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| |
Collapse
|
7
|
Ye L, Zuo Y, Chen F, Peng Q, Lu X, Wang G, Shu X. miR-18a-3p and Its Target Protein HuR May Regulate Myogenic Differentiation in Immune-Mediated Necrotizing Myopathy. Front Immunol 2022; 12:780237. [PMID: 35069550 PMCID: PMC8766969 DOI: 10.3389/fimmu.2021.780237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/13/2021] [Indexed: 11/18/2022] Open
Abstract
Immune-mediated necrotizing myopathy (IMNM) is characterized by manifestation of myonecrosis and regeneration of muscle fibers; however, the underlying pathogenesis remains unclear. This study aimed to investigate the role and mechanism of miR-18a-3p and its target RNA-binding protein HuR in IMNM. HuR and miR-18a-3p levels were detected in the skeletal muscles of 18 patients with IMNM using quantitative reverse-transcription real-time polymerase chain reaction (qRT-PCR) and western blotting analysis. Human myoblasts were transfected with small interfering RNA targeting HuR and miR-18a-3p mimic or inhibitor. Myogenic differentiation markers, myogenin and myosin heavy chain, were analyzed by qRT-PCR, western blotting analysis, and immunofluorescence staining. The results showed that miR-18a-3p was upregulated (p=0.0002), whereas HuR was downregulated (p=0.002) in the skeletal muscles of patients with IMNM. The expression of miR-18a-3p in patients with IMNM was negatively correlated with those of HuR (r = -0.512, p = 0.029). We also found that disease activity was positively correlated with HuR expression (r = 0.576, p = 0.012) but muscle activity was negatively correlated with miR-18a-3p expression (r = -0.550, p = 0.017). Besides, bioinformatics analysis and dual-luciferase reporter assays suggested that miR-18a-3p could directly target HuR. Cellular experiments showed that overexpression of miR-18a-3p inhibited myogenic differentiation by targeting HuR, whereas inhibition of miR-18a-3p led to opposite results. Therefore, miR-18a-3p and its target protein HuR may be responsible for modulating the myogenic process in IMNM and can thus be therapeutic targets for the same.
Collapse
Affiliation(s)
- Lifang Ye
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China.,Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yu Zuo
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China
| | - Fang Chen
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China
| | - Qinglin Peng
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China
| | - Xin Lu
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China
| | - Guochun Wang
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China.,Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaoming Shu
- Department of Rheumatology, Key Laboratory of Myositis, China-Japan Friendship Hospital, Beijing, China
| |
Collapse
|
8
|
Ravel-Chapuis A, Haghandish A, Daneshvar N, Jasmin BJ, Côté J. A novel CARM1-HuR axis involved in muscle differentiation and plasticity misregulated in spinal muscular atrophy. Hum Mol Genet 2021; 31:1453-1470. [PMID: 34791230 DOI: 10.1093/hmg/ddab333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by the loss of alpha motor neurons in the spinal cord and a progressive muscle weakness and atrophy. SMA is caused by loss-of-function mutations and/or deletions in the survival of motor neuron (SMN) gene. The role of SMN in motor neurons has been extensively studied, but its function and the consequences of its loss in muscle has also emerged as a key aspect of SMA pathology. In this study, we explore the molecular mechanisms involved in muscle defects in SMA. First, we show in C2C12 myoblasts, that arginine methylation by CARM1 controls myogenic differentiation. More specifically, the methylation of HuR on K217 regulates HuR levels and subcellular localization during myogenic differentiation, and the formation of myotubes. Furthermore, we demonstrate that SMN and HuR interact in C2C12 myoblasts. Interestingly, the SMA-causing E134K point mutation within the SMN Tudor domain, and CARM1 depletion, modulate the SMN-HuR interaction. In addition, using the Smn2B/- mouse model, we report that CARM1 levels are markedly increased in SMA muscles and that HuR fails to properly respond to muscle denervation, thereby affecting the regulation of its mRNA targets. Altogether, our results show a novel CARM1-HuR axis in the regulation of muscle differentiation and plasticity as well as in the aberrant regulation of this axis caused by the absence of SMN in SMA muscle. With the recent developments of therapeutics targeting motor neurons, this study further indicates the need for more global therapeutic approaches for SMA.
Collapse
Affiliation(s)
- Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Amir Haghandish
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Nasibeh Daneshvar
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| |
Collapse
|
9
|
Shi DL, Grifone R. RNA-Binding Proteins in the Post-transcriptional Control of Skeletal Muscle Development, Regeneration and Disease. Front Cell Dev Biol 2021; 9:738978. [PMID: 34616743 PMCID: PMC8488162 DOI: 10.3389/fcell.2021.738978] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/31/2021] [Indexed: 12/21/2022] Open
Abstract
Embryonic myogenesis is a temporally and spatially regulated process that generates skeletal muscle of the trunk and limbs. During this process, mononucleated myoblasts derived from myogenic progenitor cells within the somites undergo proliferation, migration and differentiation to elongate and fuse into multinucleated functional myofibers. Skeletal muscle is the most abundant tissue of the body and has the remarkable ability to self-repair by re-activating the myogenic program in muscle stem cells, known as satellite cells. Post-transcriptional regulation of gene expression mediated by RNA-binding proteins is critically required for muscle development during embryogenesis and for muscle homeostasis in the adult. Differential subcellular localization and activity of RNA-binding proteins orchestrates target gene expression at multiple levels to regulate different steps of myogenesis. Dysfunctions of these post-transcriptional regulators impair muscle development and homeostasis, but also cause defects in motor neurons or the neuromuscular junction, resulting in muscle degeneration and neuromuscular disease. Many RNA-binding proteins, such as members of the muscle blind-like (MBNL) and CUG-BP and ETR-3-like factors (CELF) families, display both overlapping and distinct targets in muscle cells. Thus they function either cooperatively or antagonistically to coordinate myoblast proliferation and differentiation. Evidence is accumulating that the dynamic interplay of their regulatory activity may control the progression of myogenic program as well as stem cell quiescence and activation. Moreover, the role of RNA-binding proteins that regulate post-transcriptional modification in the myogenic program is far less understood as compared with transcription factors involved in myogenic specification and differentiation. Here we review past achievements and recent advances in understanding the functions of RNA-binding proteins during skeletal muscle development, regeneration and disease, with the aim to identify the fundamental questions that are still open for further investigations.
Collapse
Affiliation(s)
- De-Li Shi
- Affiliated Hospital of Guangdong Medical University, Zhanjiang, China.,Developmental Biology Laboratory, CNRS-UMR 7622, Institut de Biologie de Paris-Seine, Sorbonne University, Paris, France
| | - Raphaëlle Grifone
- Developmental Biology Laboratory, CNRS-UMR 7622, Institut de Biologie de Paris-Seine, Sorbonne University, Paris, France
| |
Collapse
|
10
|
Goodman LD, Cope H, Nil Z, Ravenscroft TA, Charng WL, Lu S, Tien AC, Pfundt R, Koolen DA, Haaxma CA, Veenstra-Knol HE, Wassink-Ruiter JSK, Wevers MR, Jones M, Walsh LE, Klee VH, Theunis M, Legius E, Steel D, Barwick KES, Kurian MA, Mohammad SS, Dale RC, Terhal PA, van Binsbergen E, Kirmse B, Robinette B, Cogné B, Isidor B, Grebe TA, Kulch P, Hainline BE, Sapp K, Morava E, Klee EW, Macke EL, Trapane P, Spencer C, Si Y, Begtrup A, Moulton MJ, Dutta D, Kanca O, Wangler MF, Yamamoto S, Bellen HJ, Tan QKG. TNPO2 variants associate with human developmental delays, neurologic deficits, and dysmorphic features and alter TNPO2 activity in Drosophila. Am J Hum Genet 2021; 108:1669-1691. [PMID: 34314705 PMCID: PMC8456166 DOI: 10.1016/j.ajhg.2021.06.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/27/2021] [Indexed: 12/11/2022] Open
Abstract
Transportin-2 (TNPO2) mediates multiple pathways including non-classical nucleocytoplasmic shuttling of >60 cargoes, such as developmental and neuronal proteins. We identified 15 individuals carrying de novo coding variants in TNPO2 who presented with global developmental delay (GDD), dysmorphic features, ophthalmologic abnormalities, and neurological features. To assess the nature of these variants, functional studies were performed in Drosophila. We found that fly dTnpo (orthologous to TNPO2) is expressed in a subset of neurons. dTnpo is critical for neuronal maintenance and function as downregulating dTnpo in mature neurons using RNAi disrupts neuronal activity and survival. Altering the activity and expression of dTnpo using mutant alleles or RNAi causes developmental defects, including eye and wing deformities and lethality. These effects are dosage dependent as more severe phenotypes are associated with stronger dTnpo loss. Interestingly, similar phenotypes are observed with dTnpo upregulation and ectopic expression of TNPO2, showing that loss and gain of Transportin activity causes developmental defects. Further, proband-associated variants can cause more or less severe developmental abnormalities compared to wild-type TNPO2 when ectopically expressed. The impact of the variants tested seems to correlate with their position within the protein. Specifically, those that fall within the RAN binding domain cause more severe toxicity and those in the acidic loop are less toxic. Variants within the cargo binding domain show tissue-dependent effects. In summary, dTnpo is an essential gene in flies during development and in neurons. Further, proband-associated de novo variants within TNPO2 disrupt the function of the encoded protein. Hence, TNPO2 variants are causative for neurodevelopmental abnormalities.
Collapse
Affiliation(s)
- Lindsey D Goodman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Heidi Cope
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Zelha Nil
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Thomas A Ravenscroft
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - An-Chi Tien
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Rolph Pfundt
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, PO Box 9101, Nijmegen, the Netherlands
| | - David A Koolen
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA, PO Box 9101, Nijmegen, the Netherlands
| | - Charlotte A Haaxma
- Department of Pediatric Neurology, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Geert Grooteplein Zuid 10, 6525 GA, PO Box 9101, the Netherlands
| | - Hermine E Veenstra-Knol
- Department of Genetics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Jolien S Klein Wassink-Ruiter
- Department of Genetics, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, the Netherlands
| | - Marijke R Wevers
- Department of Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Melissa Jones
- Houston Area Pediatric Neurology, 24514 Kingsland Blvd, Katy, TX 77494, USA
| | - Laurence E Walsh
- Department of Pediatric Neurology, Riley Hospital for Children, Indianapolis, IN 46202, USA
| | - Victoria H Klee
- Department of Pediatric Neurology, Riley Hospital for Children, Indianapolis, IN 46202, USA
| | - Miel Theunis
- Center for Human Genetics, University Hospital Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Eric Legius
- Department of Human Genetics, University of Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Dora Steel
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK; Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Katy E S Barwick
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK; Department of Neurology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Shekeeb S Mohammad
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Kids Neuroscience Centre, The Children's Hospital at Westmead, Faculty of Medicine and Health, Sydney Medical School, University of Sydney, Sydney, Westmead, NSW 2145, Australia
| | - Russell C Dale
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Kids Neuroscience Centre, The Children's Hospital at Westmead, Faculty of Medicine and Health, Sydney Medical School, University of Sydney, Sydney, Westmead, NSW 2145, Australia
| | - Paulien A Terhal
- Department of Genetics, University Medical Center Utrecht, Lundlaan 6, 3584 EA Utrecht, the Netherlands
| | - Ellen van Binsbergen
- Department of Genetics, University Medical Center Utrecht, Lundlaan 6, 3584 EA Utrecht, the Netherlands
| | - Brian Kirmse
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Bethany Robinette
- Department of Pediatrics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Benjamin Cogné
- Centre hospitalier universitaire (CHU) de Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes, France; INSERM, CNRS, UNIV Nantes, Centre hospitalier universitaire (CHU) de Nantes, l'institut du thorax, 44007 Nantes, France
| | - Bertrand Isidor
- Centre hospitalier universitaire (CHU) de Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes, France; INSERM, CNRS, UNIV Nantes, Centre hospitalier universitaire (CHU) de Nantes, l'institut du thorax, 44007 Nantes, France
| | - Theresa A Grebe
- Phoenix Children's Hospital, Phoenix, AZ 85016, USA; Department of Child Health, University of Arizona College of Medicine Phoenix, Phoenix, AZ 85004, USA
| | - Peggy Kulch
- Phoenix Children's Hospital, Phoenix, AZ 85016, USA
| | - Bryan E Hainline
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Katherine Sapp
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Eva Morava
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Erica L Macke
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Pamela Trapane
- University of Florida, College of Medicine, Jacksonville, Jacksonville, FL 32209, USA
| | - Christopher Spencer
- University of Florida, College of Medicine, Jacksonville, Jacksonville, FL 32209, USA
| | - Yue Si
- GeneDx, Gaithersburg, MD 20877, USA
| | | | - Matthew J Moulton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Development, Disease Models & Therapeutics Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Queenie K-G Tan
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
| |
Collapse
|
11
|
Lv W, Jin J, Xu Z, Luo H, Guo Y, Wang X, Wang S, Zhang J, Zuo H, Bai W, Peng Y, Tang J, Zhao S, Zuo B. lncMGPF is a novel positive regulator of muscle growth and regeneration. J Cachexia Sarcopenia Muscle 2020; 11:1723-1746. [PMID: 32954689 PMCID: PMC7749533 DOI: 10.1002/jcsm.12623] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 07/24/2020] [Accepted: 08/23/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Long non-coding RNAs (lncRNAs) play critical regulatory roles in diverse biological processes and diseases. While a large number of lncRNAs have been identified in skeletal muscles until now, their function and underlying mechanisms in skeletal myogenesis remain largely unclear. METHODS We characterized a novel functional lncRNA designated lncMGPF (lncRNA muscle growth promoting factor) using RACE, Northern blot, fluorescence in situ hybridization and quantitative real-time PCR. Its function was determined by gene overexpression, interference, and knockout experiments in C2C12 myoblasts, myogenic progenitor cells, and an animal model. The molecular mechanism by which lncMGPF regulates muscle differentiation was mainly examined by cotransfection experiments, luciferase reporter assay, RNA immunoprecipitation, RNA pull-down, and RNA stability analyses. RESULTS We report that lncMGPF, which is highly expressed in muscles and positively regulated by myoblast determination factor (MyoD), promotes myogenic differentiation of muscle cells in vivo and in vitro. lncMGPF knockout in mice substantially decreases growth rate, reduces muscle mass, and impairs muscle regeneration. Overexpression of lncMGPF in muscles can rescue the muscle phenotype of knockout mice and promote muscle growth of wild-type mice. Mechanistically, lncMGPF promotes muscle differentiation by acting as a molecular sponge of miR-135a-5p and thus increasing the expression of myocyte enhancer factor 2C (MEF2C), as well as by enhancing human antigen R-mediated messenger RNA stabilization of myogenic regulatory genes such as MyoD and myogenin (MyoG). We confirm that pig lncRNA AK394747 and human lncRNA MT510647 are homologous to mouse lncMGPF, with conserved function and mechanism during myogenesis. CONCLUSIONS Our data reveal that lncMGPF is a novel positive regulator of myogenic differentiation, muscle growth and regeneration in mice, pigs, and humans.
Collapse
Affiliation(s)
- Wei Lv
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jianjun Jin
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zaiyan Xu
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China.,Department of Basic Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Hongmei Luo
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yubo Guo
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaojing Wang
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shanshan Wang
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiali Zhang
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hao Zuo
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Wei Bai
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yaxing Peng
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Junming Tang
- Hubei Key Laboratory of Embryonic Stem Cell Research, School of Basic Medicine Science, Hubei University of Medicine, Shiyan, China
| | - Shuhong Zhao
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Bo Zuo
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| |
Collapse
|
12
|
Khan AU, Qu R, Ouyang J, Dai J. Role of Nucleoporins and Transport Receptors in Cell Differentiation. Front Physiol 2020; 11:239. [PMID: 32308628 PMCID: PMC7145948 DOI: 10.3389/fphys.2020.00239] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
Bidirectional molecular movements between the nucleus and cytoplasm take place through nuclear pore complexes (NPCs) embedded in the nuclear membrane. These macromolecular structures are composed of several nucleoporins, which form seven different subcomplexes based on their biochemical affinity. These nucleoporins are integral components of the complex, not only allowing passive transport but also interacting with importin, exportin, and other molecules that are required for transport of protein in various cellular processes. Transport of different proteins is carried out either dependently or independently on transport receptors. As well as facilitating nucleocytoplasmic transport, nucleoporins also play an important role in cell differentiation, possibly by their direct gene interaction. This review will cover the general role of nucleoporins (whether its dependent or independent) and nucleocytoplasmic transport receptors in cell differentiation.
Collapse
|
13
|
Schultz CW, Preet R, Dhir T, Dixon DA, Brody JR. Understanding and targeting the disease-related RNA binding protein human antigen R (HuR). WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1581. [PMID: 31970930 DOI: 10.1002/wrna.1581] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/02/2019] [Accepted: 12/07/2019] [Indexed: 02/06/2023]
Abstract
Altered gene expression is a characteristic feature of many disease states such as tumorigenesis, and in most cancers, it facilitates cancer cell survival and adaptation. Alterations in global gene expression are strongly impacted by post-transcriptional gene regulation. The RNA binding protein (RBP) HuR (ELAVL1) is an established regulator of post-transcriptional gene regulation and is overexpressed in most human cancers. In many cancerous settings, HuR is not only overexpressed, but it is "overactive" as denoted by increased subcellular localization within the cytoplasm. This dysregulation of HuR expression and cytoplasmic localization allows HuR to stabilize and increase the translation of various prosurvival messenger RNA (mRNAs) involved in the pathogenesis of numerous cancers and various diseases. Based on almost 20 years of work, HuR is now recognized as a therapeutic target. Herein, we will review the role HuR plays in the pathophysiology of different diseases and ongoing therapeutic strategies to target HuR. We will focus on three ongoing-targeted strategies: (1) inhibiting HuR's translocation from the nucleus to the cytoplasm; (2) inhibiting the ability of HuR to bind target RNA; and (3) silencing HuR expression levels. In an oncologic setting, HuR has been demonstrated to be critical for a cancer cell's ability to survive a variety of cancer relevant stressors (including drugs and elements of the tumor microenvironment) and targeting this protein has been shown to sensitize cancer cells further to insult. We strongly believe that targeting HuR could be a powerful therapeutic target to treat different diseases, particularly cancer, in the near future. This article is categorized under: RNA in Disease and Development > RNA in Disease NRA Turnover and Surveillance > Regulation of RNA Stability Translation > Translation Regulation.
Collapse
Affiliation(s)
- Christopher W Schultz
- Department of Surgery, Jefferson Pancreas, Biliary and Related Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ranjan Preet
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas
| | - Teena Dhir
- Department of Surgery, Jefferson Pancreas, Biliary and Related Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Dan A Dixon
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas
| | - Jonathan R Brody
- Department of Surgery, Jefferson Pancreas, Biliary and Related Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| |
Collapse
|
14
|
Mubaid S, Ma JF, Omer A, Ashour K, Lian XJ, Sanchez BJ, Robinson S, Cammas A, Dormoy-Raclet V, Di Marco S, Chittur SV, Tenenbaum SA, Gallouzi IE. HuR counteracts miR-330 to promote STAT3 translation during inflammation-induced muscle wasting. Proc Natl Acad Sci U S A 2019; 116:17261-17270. [PMID: 31405989 PMCID: PMC6717253 DOI: 10.1073/pnas.1905172116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Debilitating cancer-induced muscle wasting, a syndrome known as cachexia, is lethal. Here we report a posttranscriptional pathway involving the RNA-binding protein HuR as a key player in the onset of this syndrome. Under these conditions, HuR switches its function from a promoter of muscle fiber formation to become an inducer of muscle loss. HuR binds to the STAT3 (signal transducer and activator of transcription 3) mRNA, which encodes one of the main effectors of this condition, promoting its expression both in vitro and in vivo. While HuR does not affect the stability and the cellular movement of this transcript, HuR promotes the translation of the STAT3 mRNA by preventing miR-330 (microRNA 330)-mediated translation inhibition. To achieve this effect, HuR directly binds to a U-rich element in the STAT3 mRNA-3'untranslated region (UTR) located within the vicinity of the miR-330 seed element. Even though the binding sites of HuR and miR-330 do not overlap, the recruitment of either one of them to the STAT3-3'UTR negatively impacts the binding and the function of the other factor. Therefore, together, our data establish the competitive interplay between HuR and miR-330 as a mechanism via which muscle fibers modulate, in part, STAT3 expression to determine their fate in response to promoters of muscle wasting.
Collapse
Affiliation(s)
- Souad Mubaid
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Jennifer F Ma
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Amr Omer
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Kholoud Ashour
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Xian J Lian
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Brenda J Sanchez
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Samantha Robinson
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Anne Cammas
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France
- Université Toulouse III Paul Sabatier, 31330 Toulouse, France
- Laboratoire d'Excellence "TOUCAN," 31037 Toulouse, France
| | - Virginie Dormoy-Raclet
- Laboratoire de Génétique Moléculaire, Centre Hospitalier Universitaire de Bordeaux, 33076 Bordeaux Cedex, France
| | - Sergio Di Marco
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Sridar V Chittur
- College of Nanoscale Sciences, State University of New York (SUNY) Polytechnic Institute, Albany, NY 12203
- College of Engineering, SUNY Polytechnic Institute, Albany, NY 12203
| | - Scott A Tenenbaum
- College of Nanoscale Sciences, State University of New York (SUNY) Polytechnic Institute, Albany, NY 12203
- College of Engineering, SUNY Polytechnic Institute, Albany, NY 12203
| | - Imed-Eddine Gallouzi
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, QC H3G 1Y6, Canada;
| |
Collapse
|
15
|
Phillips BL, Banerjee A, Sanchez BJ, Di Marco S, Gallouzi IE, Pavlath GK, Corbett AH. Post-transcriptional regulation of Pabpn1 by the RNA binding protein HuR. Nucleic Acids Res 2019; 46:7643-7661. [PMID: 29939290 PMCID: PMC6125628 DOI: 10.1093/nar/gky535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/08/2018] [Indexed: 01/14/2023] Open
Abstract
RNA processing is critical for proper spatial and temporal control of gene expression. The ubiquitous nuclear polyadenosine RNA binding protein, PABPN1, post-transcriptionally regulates multiple steps of gene expression. Mutations in the PABPN1 gene expanding an N-terminal alanine tract in the PABPN1 protein from 10 alanines to 11–18 alanines cause the muscle-specific disease oculopharyngeal muscular dystrophy (OPMD), which affects eyelid, pharynx, and proximal limb muscles. Previous work revealed that the Pabpn1 transcript is unstable, contributing to low steady-state Pabpn1 mRNA and protein levels in vivo, specifically in skeletal muscle, with even lower levels in muscles affected in OPMD. Thus, low levels of PABPN1 protein could predispose specific tissues to pathology in OPMD. However, no studies have defined the mechanisms that regulate Pabpn1 expression. Here, we define multiple cis-regulatory elements and a trans-acting factor, HuR, which regulate Pabpn1 expression specifically in mature muscle in vitro and in vivo. We exploit multiple models including C2C12 myotubes, primary muscle cells, and mice to determine that HuR decreases Pabpn1 expression. Overall, we have uncovered a mechanism in mature muscle that negatively regulates Pabpn1 expression in vitro and in vivo, which could provide insight to future studies investigating therapeutic strategies for OPMD treatment.
Collapse
Affiliation(s)
- Brittany L Phillips
- Department of Biology, Emory University, Atlanta, GA 30322, USA.,Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA 30322, USA
| | - Ayan Banerjee
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Brenda J Sanchez
- Department of Biochemistry, Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
| | - Sergio Di Marco
- Department of Biochemistry, Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
| | - Imed-Eddine Gallouzi
- Department of Biochemistry, Goodman Cancer Center, McGill University, Montreal, Quebec, Canada.,Hamad Bin Khalifa University (HBKU), Life Sciences Division, College of Sciences and Engineering, Education City, Doha, Qatar
| | - Grace K Pavlath
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| |
Collapse
|
16
|
Reprint of: Importins in the maintenance and lineage commitment of ES cells. Neurochem Int 2017; 106:14-23. [PMID: 28550879 DOI: 10.1016/j.neuint.2017.01.022] [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: 08/31/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/23/2022]
Abstract
The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.
Collapse
|
17
|
Importins in the maintenance and lineage commitment of ES cells. Neurochem Int 2017; 105:32-41. [PMID: 28163061 DOI: 10.1016/j.neuint.2017.01.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/23/2022]
Abstract
The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.
Collapse
|
18
|
Grammatikakis I, Abdelmohsen K, Gorospe M. Posttranslational control of HuR function. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27307117 DOI: 10.1002/wrna.1372] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 12/28/2022]
Abstract
The RNA-binding protein HuR (human antigen R) associates with numerous transcripts, coding and noncoding, and controls their splicing, localization, stability, and translation. Through its regulation of target transcripts, HuR has been implicated in cellular events including proliferation, senescence, differentiation, apoptosis, and the stress and immune responses. In turn, HuR influences processes such as cancer and inflammation. HuR function is primarily regulated through posttranslational modifications that alter its subcellular localization and its ability to bind target RNAs; such modifications include phosphorylation, methylation, ubiquitination, NEDDylation, and proteolytic cleavage. In this review, we describe the modifications that impact upon HuR function on gene expression programs and disease states. WIREs RNA 2017, 8:e1372. doi: 10.1002/wrna.1372 For further resources related to this article, please visit the WIREs website.
Collapse
Affiliation(s)
- Ioannis Grammatikakis
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Kotb Abdelmohsen
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Myriam Gorospe
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| |
Collapse
|
19
|
Scheiba RM, de Opakua AI, Díaz-Quintana A, Cruz-Gallardo I, Martínez-Cruz LA, Martínez-Chantar ML, Blanco FJ, Díaz-Moreno I. The C-terminal RNA binding motif of HuR is a multi-functional domain leading to HuR oligomerization and binding to U-rich RNA targets. RNA Biol 2015; 11:1250-61. [PMID: 25584704 DOI: 10.1080/15476286.2014.996069] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human antigen R (HuR) is a 32 kDa protein with 3 RNA Recognition Motifs (RRMs), which bind to Adenylate and uridylate Rich Elements (AREs) of mRNAs. Whereas the N-terminal and central domains (RRM1 and RRM2) are essential for AREs recognition, little is known on the C-terminal RRM3 beyond its implication in HuR oligomerization and apoptotic signaling. We have developed a detergent-based strategy to produce soluble RRM3 for structural studies. We have found that it adopts the typical RRM fold, does not interact with the RRM1 and RRM2 modules, and forms dimers in solution. Our NMR measurements, combined with Molecular Dynamics simulations and Analytical Ultracentrifugation experiments, show that the protein dimerizes through a helical region that contains the conserved W261 residue. We found that HuR RRM3 binds to 5'-mer U-rich RNA stretches through the solvent exposed side of its β-sheet, located opposite to the dimerization site. Upon mimicking phosphorylation by the S318D replacement, RRM3 mutant shows less ability to recognize RNA due to an electrostatic repulsion effect with the phosphate groups. Our study brings new insights of HuR RRM3 as a domain involved in protein oligomerization and RNA interaction, both functions regulated by 2 surfaces on opposite sides of the RRM domain.
Collapse
Key Words
- AREs, Adenylate and uridylate Rich Elements
- AU, Analytical Ultracentrifugation
- CARM1, Coactivator associated Arginine Methyltransferase 1
- CD, Circular Dichroism
- Cdk1, Cyclin-dependent kinase 1
- Chk2, Checkpoint kinase 2
- ELAV1, Embryonic Lethal Abnormal Vision system human homolog 1
- EMSA, Electrophoretic Mobility Shift Assay
- FIR, FBP-Interacting Repressor
- FL, Full-Length, HNS, HuR Nucleocytoplasmic Shuttling Sequence
- HSQC, Heteronuclear Single-Quantum Correlation
- HuR, Human antigen R
- Human antigen R (HuR)
- MD, Molecular Dynamics
- NMR, Nuclear Magnetic Resonance
- NOE, Nuclear Overhauser Effect
- Nuclear Magnetic Resonance (NMR)
- PCA, Principal Component Analysis
- PKCα, Protein Kinase C α
- PKCδ, Protein Kinase C δ
- PMSF, PhenylMethylSulfonyl Fluoride
- PTB, Polypyrimidine Tract Binding protein
- RBPs, RNA Binding Proteins
- RNA binding
- RNA binding protein (RBP)
- RNA recognition motif (RRM)
- RRMs, RNA Recognition Motifs
- SPR, Surface Plasmon Resonance
- Serine Phosphorylation
- WT, Wild-Type
- dimerization
- hnRNP1, heterogeneous nuclear RiboNucleoprotein C protein
Collapse
Affiliation(s)
- Rafael M Scheiba
- a Instituto de Bioquímica Vegetal y Fotosíntesis; cicCartuja ; Sevilla , Spain
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Cammas A, Sanchez BJ, Lian XJ, Dormoy-Raclet V, van der Giessen K, López de Silanes I, Ma J, Wilusz C, Richardson J, Gorospe M, Millevoi S, Giovarelli M, Gherzi R, Di Marco S, Gallouzi IE. Destabilization of nucleophosmin mRNA by the HuR/KSRP complex is required for muscle fibre formation. Nat Commun 2014; 5:4190. [PMID: 24969639 PMCID: PMC4074165 DOI: 10.1038/ncomms5190] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/21/2014] [Indexed: 01/03/2023] Open
Abstract
HuR promotes myogenesis by stabilizing the MyoD, myogenin and p21 mRNAs during the fusion of muscle cells to form myotubes. Here we show that HuR, via a novel mRNA destabilizing activity, promotes the early steps of myogenesis by reducing the expression of the cell cycle promoter nucleophosmin (NPM). Depletion of HuR stabilizes the NPM mRNA, increases NPM protein levels and inhibits myogenesis, while its overexpression elicits the opposite effects. NPM mRNA destabilization involves the association of HuR with the decay factor KSRP as well as the ribonuclease PARN and the exosome. The C terminus of HuR mediates the formation of the HuR-KSRP complex and is sufficient for maintaining a low level of the NPM mRNA as well as promoting the commitment of muscle cells to myogenesis. We therefore propose a model whereby the downregulation of the NPM mRNA, mediated by HuR, KSRP and its associated ribonucleases, is required for proper myogenesis.
Collapse
Affiliation(s)
- Anne Cammas
- 1] Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6 [2] INSERM, UMR 1037, Centre de Recherche en Cancérologie de Toulouse, 31432 Toulouse, France
| | - Brenda Janice Sanchez
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Xian Jin Lian
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Virginie Dormoy-Raclet
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Kate van der Giessen
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Isabel López de Silanes
- Spanish National Cancer Research Centre (CNIO) Telomeres and Telomerase Group, Molecular Oncology Program, C/ Melchor Fernández Almagro, 3, 28029 Madrid, Spain
| | - Jennifer Ma
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Carol Wilusz
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, USA
| | - John Richardson
- Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A2B4
| | - Myriam Gorospe
- National Institute on Aging, National Institutes of Health, Biomedical Research Center, Room 06C226, 251 Bayview Boulevard, Suite 100, Baltimore, Maryland 21224-6825, USA
| | - Stefania Millevoi
- INSERM, UMR 1037, Centre de Recherche en Cancérologie de Toulouse, 31432 Toulouse, France
| | - Matteo Giovarelli
- Istituto Nazionale Ricerca sul Cancro (IST), Laboratory of Gene Expression Regulation, c/o CBA Building A3, Room 30, Largo R. Benzi, 10, 16132 Genova, Italy
| | - Roberto Gherzi
- Istituto Nazionale Ricerca sul Cancro (IST), Laboratory of Gene Expression Regulation, c/o CBA Building A3, Room 30, Largo R. Benzi, 10, 16132 Genova, Italy
| | - Sergio Di Marco
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| | - Imed-Eddine Gallouzi
- Department of Biochemistry, Goodman Cancer Center, McGill University, McIntyre Building Room 915B, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
| |
Collapse
|
21
|
Kimura M, Imamoto N. Biological significance of the importin-β family-dependent nucleocytoplasmic transport pathways. Traffic 2014; 15:727-48. [PMID: 24766099 DOI: 10.1111/tra.12174] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 12/19/2022]
Abstract
Importin-β family proteins (Imp-βs) are nucleocytoplasmic transport receptors (NTRs) that import and export proteins and RNAs through the nuclear pores. The family consists of 14-20 members depending on the biological species, and each member transports a specific group of cargoes. Thus, the Imp-βs mediate multiple, parallel transport pathways that can be regulated separately. In fact, the spatiotemporally differential expressions and the functional regulations of Imp-βs have been reported. Additionally, the biological significance of each pathway has been characterized by linking the function of a member of Imp-βs to a cellular consequence. Connecting these concepts, the regulation of the transport pathways conceivably induces alterations in the cellular physiological states. However, few studies have linked the regulation of an importin-β family NTR to an induced cellular response and the corresponding cargoes, despite the significance of this linkage in comprehending the biological relevance of the transport pathways. This review of recent reports on the regulation and biological functions of the Imp-βs highlights the significance of the transport pathways in physiological contexts and points out the possibility that the identification of yet unknown specific cargoes will reinforce the importance of transport regulation.
Collapse
Affiliation(s)
- Makoto Kimura
- Cellular Dynamics Laboratory, RIKEN, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | | |
Collapse
|
22
|
Twyffels L, Gueydan C, Kruys V. Transportin-1 and Transportin-2: protein nuclear import and beyond. FEBS Lett 2014; 588:1857-68. [PMID: 24780099 DOI: 10.1016/j.febslet.2014.04.023] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/12/2014] [Accepted: 04/16/2014] [Indexed: 12/22/2022]
Abstract
Nearly 20 years after its identification as a new β-karyopherin mediating the nuclear import of the RNA-binding protein hnRNP A1, Transportin-1 is still commonly overlooked in comparison with its best known cousin, Importin-β. Transportin-1 is nonetheless a considerable player in nucleo-cytoplasmic transport. Over the past few years, significant progress has been made in the characterization of the nuclear localization signals (NLSs) that Transportin-1 recognizes, thereby providing the molecular basis of its diversified repertoire of cargoes. The recent discovery that mutations in the Transportin-dependent NLS of FUS cause mislocalization of this protein and result in amyotrophic lateral sclerosis illustrates the importance of Transportin-dependent import for human health. Besides, new functions of Transportin-1 are emerging in processes other than nuclear import. Here, we summarize what is known about Transportin-1 and the related β-karyopherin Transportin-2.
Collapse
Affiliation(s)
- Laure Twyffels
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium.
| | - Cyril Gueydan
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium
| | - Véronique Kruys
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium
| |
Collapse
|
23
|
HuR and miR-1192 regulate myogenesis by modulating the translation of HMGB1 mRNA. Nat Commun 2014; 4:2388. [PMID: 24005720 PMCID: PMC4005793 DOI: 10.1038/ncomms3388] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/02/2013] [Indexed: 12/14/2022] Open
Abstract
Upon muscle injury, the high mobility group box 1 (HMGB1) protein is upregulated and secreted to initiate reparative responses. Here we show that HMGB1 controls myogenesis both in vitro and in vivo during development and after adult muscle injury. HMGB1 expression in muscle cells is regulated at the translational level: the miRNA miR-1192 inhibits HMGB1 translation and the RNA-binding protein HuR promotes it. HuR binds to a cis-element, HuR binding sites (HuRBS), located in the 3'UTR of the HMGB1 transcript, and at the same time miR-1192 is recruited to an adjacent seed element. The binding of HuR to the HuRBS prevents the recruitment of Argonaute 2 (Ago2), overriding miR-1192-mediated translation inhibition. Depleting HuR reduces myoblast fusion and silencing miR-1192 re-establishes the fusion potential of HuR-depleted cells. We propose that HuR promotes the commitment of myoblasts to myogenesis by enhancing the translation of HMGB1 and suppressing the translation inhibition mediated by miR-1192.
Collapse
|
24
|
Abstract
Classic nuclear shuttling is mediated by an importin-α∙β heterodimer that binds to cargoes containing a nuclear localization signal, and shuttles most nuclear proteins immediately after their translation. Aside from this canonical mechanism, kariopheryn-βs or β-like importins operate by binding to non-canonical nuclear localization signals to mediate translocation without the assistance of importin-α. The mechanism by which these components operate is much less understood and is currently under investigation. Recently, several β-like importins have been implicated in the stimulated nuclear translocation of signaling proteins. Here, we propose that this group of importins might be responsible for the swift nuclear shuttling of many proteins following various stimuli.
Collapse
|
25
|
Zago M, Sheridan JA, Nair P, Rico de Souza A, Gallouzi IE, Rousseau S, Di Marco S, Hamid Q, Eidelman DH, Baglole CJ. Aryl hydrocarbon receptor-dependent retention of nuclear HuR suppresses cigarette smoke-induced cyclooxygenase-2 expression independent of DNA-binding. PLoS One 2013; 8:e74953. [PMID: 24086407 PMCID: PMC3785509 DOI: 10.1371/journal.pone.0074953] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/07/2013] [Indexed: 12/02/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that responds to man-made environmental toxicants, has emerged as an endogenous regulator of cyclooxygenase-2 (Cox-2) by a mechanism that is poorly understood. In this study, we first used AhR-deficient (AhR−/−) primary pulmonary cells, together with pharmacological tools to inhibit new RNA synthesis, to show that the AhR is a prominent factor in the destabilization of Cox-2 mRNA. The destabilization of Cox-2 mRNA and subsequent suppression of cigarette smoke-induced COX-2 protein expression by the AhR was independent of its ability to bind the dioxin response element (DRE), thereby differentiating the DRE-driven toxicological AhR pathway from its anti-inflammatory abilities. We further describe that the AhR destabilizes Cox-2 mRNA by sequestering HuR within the nucleus. The role of HuR in AhR stabilization of Cox-2 mRNA was confirmed by knockdown of HuR, which resulted in rapid Cox-2 mRNA degradation. Finally, in the lungs of AhR−/− mice exposed to cigarette smoke, there was little Cox-2 mRNA despite robust COX-2 protein expression, a finding that correlates with almost exclusive cytoplasmic HuR within the lungs of AhR−/− mice. Therefore, we propose that the AhR plays an important role in suppressing the expression of inflammatory proteins, a function that extends beyond the ability of the AhR to respond to man-made toxicants. These findings open the possibility that a DRE-independent AhR pathway may be exploited therapeutically as an anti-inflammatory target.
Collapse
MESH Headings
- Animals
- Azo Compounds/pharmacology
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Cells, Cultured
- Cyclooxygenase 2/genetics
- Cyclooxygenase 2/metabolism
- DNA/metabolism
- ELAV Proteins/metabolism
- Fibroblasts/drug effects
- Fibroblasts/enzymology
- Fibroblasts/pathology
- Humans
- Lung/pathology
- Mice
- Models, Biological
- Prostaglandins/biosynthesis
- Protein Binding/drug effects
- Protein Structure, Tertiary
- Protein Transport/drug effects
- Pyrazoles/pharmacology
- RNA Stability/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/metabolism
- Receptors, Aryl Hydrocarbon/antagonists & inhibitors
- Receptors, Aryl Hydrocarbon/chemistry
- Receptors, Aryl Hydrocarbon/deficiency
- Receptors, Aryl Hydrocarbon/metabolism
- Smoking/adverse effects
Collapse
Affiliation(s)
- Michela Zago
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | | | - Parameswaran Nair
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Angela Rico de Souza
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Imed-Eddine Gallouzi
- Department of Biochemistry and the Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Simon Rousseau
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Sergio Di Marco
- Department of Biochemistry and the Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Qutayba Hamid
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - David H. Eidelman
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Carolyn J. Baglole
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- * E-mail:
| |
Collapse
|
26
|
Pang L, Tian H, Chang N, Yi J, Xue L, Jiang B, Gorospe M, Zhang X, Wang W. Loss of CARM1 is linked to reduced HuR function in replicative senescence. BMC Mol Biol 2013; 14:15. [PMID: 23837869 PMCID: PMC3718661 DOI: 10.1186/1471-2199-14-15] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/02/2013] [Indexed: 11/15/2022] Open
Abstract
Background The co-activator-associated arginine methyltransferase 1 (CARM1) catalyzes the methylation of HuR. However, the functional impact of this modification is not fully understood. Here, we investigated the influence of HuR methylation by CARM1 upon the turnover of HuR target mRNAs encoding senescence-regulatory proteins. Results Changing the methylation status of HuR in HeLa cells by either silencing CARM1 or mutating the major methylation site (R217K) greatly diminished the effect of HuR in regulating the turnover of mRNAs encoding cyclin A, cyclin B1, c-fos, SIRT1, and p16. Although knockdown of CARM1 or HuR individually influenced the expression of cyclin A, cyclin B1, c-fos, SIRT1, and p16, joint knockdown of both CARM1 and HuR did not show further effect. Methylation by CARM1 enhanced the association of HuR with the 3′UTR of p16 mRNA, but not with the 3′UTR of cyclin A, cyclin B1, c-fos, or SIRT1 mRNAs. In senescent human diploid fibroblasts (HDFs), reduced CARM1 was accompanied by reduced HuR methylation. In addition, knockdown of CARM1 or mutation of the major methylation site of HuR in HDF markedly impaired the ability of HuR to regulate the expression of cyclin A, cyclin B1, c-fos, SIRT1, and p16 as well to maintain a proliferative phenotype. Conclusion CARM1 represses replicative senescence by methylating HuR and thereby enhancing HuR’s ability to regulate the turnover of cyclin A, cyclin B1, c-fos, SIRT1, and p16 mRNAs.
Collapse
Affiliation(s)
- Lijun Pang
- Department of Biochemistry and Molecular Biology, Peking University health Science Center, 38 Xueyuan Road, Beijing 100191, P. R. China
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Impairment of FOS mRNA stabilization following translation arrest in granulocytes from myelodysplastic syndrome patients. PLoS One 2013; 8:e61107. [PMID: 23593403 PMCID: PMC3625160 DOI: 10.1371/journal.pone.0061107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 03/05/2013] [Indexed: 02/06/2023] Open
Abstract
Although quantitative and qualitative granulocyte defects have been described in myelodysplastic syndromes (MDS), the underlying molecular basis of granulocyte dysfunction in MDS is largely unknown. We recently found that FOS mRNA elevation under translation-inhibiting stimuli was significantly smaller in granulocytes from MDS patients than in healthy individuals. The aim of this study is to clarify the cause of the impaired FOS induction in MDS. We first examined the mechanisms of FOS mRNA elevation using granulocytes from healthy donors cultured with the translation inhibitor emetine. Emetine increased both transcription and mRNA stability of FOS. p38 MAPK inhibition abolished the emetine-induced increase of FOS transcription but did not affect FOS mRNA stabilization. The binding of an AU-rich element (ARE)-binding protein HuR to FOS mRNA containing an ARE in 3'UTR was increased by emetine, and the knockdown of HuR reduced the FOS mRNA stabilizing effect of emetine. We next compared the emetine-induced transcription and mRNA stabilization of FOS between MDS patients and healthy controls. Increased rates of FOS transcription by emetine were similar in MDS and controls. In the absence of emetine, FOS mRNA decayed to nearly 17% of initial levels in 45 min in both groups. In the presence of emetine, however, 76.7±19.8% of FOS mRNA remained after 45 min in healthy controls, versus 37.9±25.5% in MDS (P<0.01). To our knowledge, this is the first report demonstrating attenuation of stress-induced FOS mRNA stabilization in MDS granulocytes.
Collapse
|
28
|
Nuclear pore complex composition: a new regulator of tissue-specific and developmental functions. Nat Rev Mol Cell Biol 2013; 13:687-99. [PMID: 23090414 DOI: 10.1038/nrm3461] [Citation(s) in RCA: 241] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Nuclear pore complexes (NPCs) are multiprotein aqueous channels that penetrate the nuclear envelope connecting the nucleus and the cytoplasm. NPCs consist of multiple copies of roughly 30 different proteins known as nucleoporins (NUPs). Due to their essential role in controlling nucleocytoplasmic transport, NPCs have traditionally been considered as structures of ubiquitous composition. The overall structure of the NPC is indeed conserved in all cells, but new evidence suggests that the protein composition of NPCs varies among cell types and tissues. Moreover, mutations in various nucleoporins result in tissue-specific diseases. These findings point towards a heterogeneity in NPC composition and function. This unexpected heterogeneity suggests that cells use a combination of different nucleoporins to assemble NPCs with distinct properties and specialized functions.
Collapse
|
29
|
von Roretz C, Lian XJ, Macri AM, Punjani N, Clair E, Drouin O, Dormoy-Raclet V, Ma JF, Gallouzi IE. Apoptotic-induced cleavage shifts HuR from being a promoter of survival to an activator of caspase-mediated apoptosis. Cell Death Differ 2012; 20:154-68. [PMID: 22955946 DOI: 10.1038/cdd.2012.111] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Little is known about the cellular mechanisms modulating the shift in balance from a state of survival to cell death by caspase-mediated apoptosis in response to a lethal stress. Here we show that the RNA-binding protein HuR has an important function in mediating this switch. During caspase-mediated apoptosis, HuR is cleaved to generate two cleavage products (CPs). Our data demonstrate that the cleavage of HuR switches its function from being a prosurvival factor under normal conditions to becoming a promoter of apoptosis in response to a lethal stress. In the absence of an apoptotic stimuli, HuR associates with and promotes the expression of caspase-9 and prothymosin α (ProT) mRNAs, and pro- and antiapoptotic factors, respectively, both of which have been characterized as important players in determining cell fate. During the early steps of caspase-mediated apoptosis, however, the level of caspase-9 protein increases, while ProT remains unchanged. Under these conditions, the two HuR-CPs selectively bind to and stabilize caspase-9 mRNA, but do not bind to ProT. Hence, taken together, our data show that by maintaining a threshold of expression of proapoptotic factors such as caspase-9 in response to a lethal stress, the HuR-CPs help a cell to switch from resisting death to undergoing apoptosis.
Collapse
Affiliation(s)
- C von Roretz
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Downregulation of HuR as a new mechanism of doxorubicin resistance in breast cancer cells. Mol Cancer 2012; 11:13. [PMID: 22436134 PMCID: PMC3325864 DOI: 10.1186/1476-4598-11-13] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 03/21/2012] [Indexed: 11/10/2022] Open
Abstract
Background HuR, an RNA binding protein involved in the post-transcriptional regulation of a wide spectrum of mRNAs, has been demonstrated to be a determinant of carcinogenesis and tumor aggressiveness in several cancer types. In this study, we investigated the role of HuR in the apoptosis and in the chemoresistance induced by the widely used anticancer drug doxorubicin in human breast cancer cells (MCF-7). Results We showed that HuR acts in the early phase of cell response to doxorubicin, being induced to translocate into the cytoplasm upon phosphorylation. Reducing HuR levels diminished the apoptotic response to doxorubicin. Doxorubicin-induced apoptosis was also correlated with the presence of HuR in the cytoplasm. Rottlerin, which was able to block HuR nuclear export, had correspondingly antagonistic effects with doxorubicin on cell toxicity. The proapoptotic activity of HuR was not due to cleavage to an active form, as was previously reported. In in vitro selected doxorubicin resistant MCF-7 cells (MCF-7/doxoR) overexpressing the multidrug resistance (MDR) related ABCG2 transporter, we observed a significant HuR downregulation that was paralleled by a corresponding downregulation of HuR targets and by loss of rottlerin toxicity. Restoration of HuR expression in these cells resensitized MCF-7/doxoR cells to doxorubicin, reactivating the apoptotic response. Conclusions The present study shows that HuR is necessary to elicit the apoptotic cell response to doxorubicin and that restoration of HuR expression in resistant cells resensitizes them to the action of this drug, thereby identifying HuR as a key protein in doxorubicin pharmacology.
Collapse
|
31
|
Gomez-Santos L, Vazquez-Chantada M, Mato JM, Martinez-Chantar ML. SAMe and HuR in liver physiology: usefulness of stem cells in hepatic differentiation research. Methods Mol Biol 2012; 826:133-49. [PMID: 22167646 DOI: 10.1007/978-1-61779-468-1_12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
S-Adenosylmethionine, abbreviated as SAM, SAMe or AdoMet, is the principal methyl group donor in the mammalian cell and the first step metabolite of the methionine cycle, being synthesized by MAT (methionine adenosyltransferase) from methionine and ATP. About 60 years after its identification, SAMe is admitted as a key hepatic regulator whose level needs to be maintained within a specific range in order to avoid liver damage. Recently, in vitro and in vivo studies have demonstrated the regulatory role of SAMe in HGF (hepatocyte growth factor)-mediated hepatocyte proliferation through a mechanism that implicates the activation of the non-canonical LKB1/AMPK/eNOS cascade and HuR function. Regarding hepatic differentiation, cellular SAMe content varies depending on the status of the cell, being lower in immature than in adult hepatocytes. This finding suggests a SAMe regulatory effect also in this cellular process, which very recently was reported and related to HuR activity. Although in the last years this and other discoveries contributed to throw light into the tangle of regulatory mechanisms that govern this complex process, an overall understanding is still a challenge. For this purpose, the in vitro hepatic differentiation culture systems by using stem cells or fetal hepatoblasts are considered as valuable tools which, in combination with the methods used in current days to elucidate cell signaling pathways, surely will help to clear up this question.
Collapse
Affiliation(s)
- Laura Gomez-Santos
- Metabolomics Unit, CIC bioGUNE, Technology Park of Bizkaia, Bizkaia, Basque Country, Spain.
| | | | | | | |
Collapse
|
32
|
Yamaguchi Y, Naiki T, Irie K. Stau1 regulates Dvl2 expression during myoblast differentiation. Biochem Biophys Res Commun 2011; 417:427-32. [PMID: 22166206 DOI: 10.1016/j.bbrc.2011.11.133] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 11/29/2011] [Indexed: 11/19/2022]
Abstract
Post-transcriptional regulation of gene expression by RNA-binding proteins has pivotal roles in many biological processes. We have shown that Stau1, a conserved RNA-binding protein, negatively regulates myogenesis in C2C12 myoblasts. However, its target mRNAs in regulation of myogenesis remain unknown. Here we describe that Stau1 positively regulates expression of Dvl2 gene encoding a central mediator of Wnt pathway in undifferentiated C2C12 myoblasts. Stau1 binds to 3' untranslated region (UTR) of Dvl2 mRNA and Stau1 knockdown shortened a half-life of the mRNA containing Dvl2 3' UTR. After induction of myogenic differentiation, association of Stau1 with 3' UTR of Dvl2 mRNA was decreased. Correlated with the decrease in the association, the Dvl2 mRNA level was reduced during myogenesis. A forced expression of Dvl2 markedly inhibited progression of myogenic differentiation. Our results suggest that Dvl2 has an inhibitory role in myogenesis and Stau1 coordinates myogenesis through the regulation of Dvl2 mRNA.
Collapse
Affiliation(s)
- Yukio Yamaguchi
- Department of Molecular Cell Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | | | | |
Collapse
|
33
|
von Roretz C, Macri AM, Gallouzi IE. Transportin 2 regulates apoptosis through the RNA-binding protein HuR. J Biol Chem 2011; 286:25983-91. [PMID: 21646354 DOI: 10.1074/jbc.m110.216184] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In response to severe stress, apoptotic cell death is engaged. Apoptosis is a well orchestrated process that involves the activation and implication of many factors. In this study, we identified a role for the nuclear trafficking factor TRN2 (transportin 2) in cell death. TRN2 is normally responsible for the nuclear import of the RNA-binding protein HuR. During apoptosis, however, HuR accumulates in the cytoplasm. This is due to the caspase-mediated cleavage of the cytoplasmic fraction of HuR. One of the cleavage fragments generated by this processing of HuR interacts with TRN2 and thus blocks the re-import of HuR into the nucleus. This concentrates HuR in the cytoplasm, advancing apoptosis. Therefore, increasing or decreasing the levels of TRN2 has an inverse consequential effect on cell death, demonstrating for the first time the role of a nucleocytoplasmic transport factor in apoptosis.
Collapse
Affiliation(s)
- Christopher von Roretz
- Department of Biochemistry and Rosalind and Morris Goodman Cancer Center, McGill University, Montreal, Quebec, Canada
| | | | | |
Collapse
|
34
|
Sgantzis N, Yiakouvaki A, Remboutsika E, Kontoyiannis DL. HuR controls lung branching morphogenesis and mesenchymal FGF networks. Dev Biol 2011; 354:267-79. [PMID: 21515253 DOI: 10.1016/j.ydbio.2011.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022]
Abstract
Lung development is controlled by regulatory networks governing mesenchymal-epithelial interactions. Transcription factors and signaling molecules are known to participate in this process, yet little is known about the post-transcriptional regulation of these networks. Here we demonstrate that the RNA-binding protein (RBP) HuR is an essential regulator of mesenchymal responses during lung branching. Its epiblast-induced deletion blocked the morphogenesis of distal bronchial branches at the initiation of the pseudoglandular stage. The phenotype originated from defective mesenchymal responses since the conditional restriction of HuR deletion in epithelial progenitors did not affect distal branching or the completion of lung maturation. The loss of HuR resulted in the reduction of the key inducer of bud outgrowth and endodermal branching, FGF10 and one of its putative transcriptional regulators, Tbx4. Furthermore, exogenous FGF10 could rescue the branching defect of affected lung buds. HuR was found to bind and control the Fgf10 and Tbx4 mRNAs; as a result its deletion abolished their inducible post-transcriptional regulation by the mesenchymal regulator FGF9. Our data reveals HuR as the first RBP identified to play a dominant role in lung development and as a key post-transcriptional regulator of networks guiding tissue remodeling during branching morphogenesis.
Collapse
Affiliation(s)
- Nikos Sgantzis
- Institute of Immunology, Biomedical Sciences Research Center "Alexander Fleming", 16672 Vari, Greece
| | | | | | | |
Collapse
|
35
|
von Roretz C, Beauchamp P, Di Marco S, Gallouzi IE. HuR and myogenesis: being in the right place at the right time. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1663-7. [PMID: 21315776 DOI: 10.1016/j.bbamcr.2011.01.036] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 01/20/2011] [Accepted: 01/28/2011] [Indexed: 01/23/2023]
Abstract
The process of muscle cell differentiation into myotubes, termed myogenesis, depends on a complex coordination of myogenic factors, many of which are regulated post-transcriptionally. HuR, an mRNA-binding protein, is responsible for regulating the expression of several such myogenic factors by stabilizing their mRNAs. The critical role for HuR in myogenesis also involves the nucleocytoplasmic shuttling ability of this protein. Indeed, in order to perform its stabilizing functions, HuR must accumulate in the cytoplasm. This requires its dissociation from the import factor Transportin 2 (TRN2) which is actually caused by the cleavage of a portion of cytoplasmic HuR. In this review, we describe the roles of HuR during myogenesis, and the mechanisms regulating its cytoplasmic accumulation. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
Collapse
Affiliation(s)
- Christopher von Roretz
- McGill University, Biochemistry Department and Rosalind and Morris Goodman Cancer Center, McGill University Montreal, Canada
| | | | | | | |
Collapse
|
36
|
Hall MN, Corbett AH, Pavlath GK. Regulation of nucleocytoplasmic transport in skeletal muscle. Curr Top Dev Biol 2011; 96:273-302. [PMID: 21621074 DOI: 10.1016/b978-0-12-385940-2.00010-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Proper skeletal muscle function is dependent on spatial and temporal control of gene expression in multinucleated myofibers. In addition, satellite cells, which are tissue-specific stem cells that contribute critically to repair and maintenance of skeletal muscle, are also required for normal muscle physiology. Gene expression in both myofibers and satellite cells is dependent upon nuclear proteins that require facilitated nuclear transport. A unique challenge for myofibers is controlling the transcriptional activity of hundreds of nuclei in a common cytoplasm yet achieving nuclear selectivity in transcription at specific locations such as neuromuscular synapses and myotendinous junctions. Nucleocytoplasmic transport of macromolecular cargoes is regulated by a complex interplay among various components of the nuclear transport machinery, namely nuclear pore complexes, nuclear envelope proteins, and various soluble transport receptors. The focus of this review is to highlight what is known about the nuclear transport machinery and its regulation in skeletal muscle and to consider the unique challenges that multinucleated muscle cells as well as satellite cells encounter in regulating nucleocytoplasmic transport during cell differentiation and tissue adaptation. Understanding how regulated nucleocytoplasmic transport controls gene expression in skeletal muscle may lead to further insights into the mechanisms contributing to muscle growth and maintenance throughout the lifespan of an individual.
Collapse
Affiliation(s)
- Monica N Hall
- Graduate Program in Genetics and Molecular Biology, Emory University, Atlanta, Georgia, USA
| | | | | |
Collapse
|
37
|
von Roretz C, Gallouzi IE. Protein kinase RNA/FADD/caspase-8 pathway mediates the proapoptotic activity of the RNA-binding protein human antigen R (HuR). J Biol Chem 2010; 285:16806-13. [PMID: 20353946 PMCID: PMC2878037 DOI: 10.1074/jbc.m109.087320] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 03/04/2010] [Indexed: 11/06/2022] Open
Abstract
The RNA-binding protein human antigen R (HuR) has been implicated in apoptosis in multiple ways. Several studies have shown that in response to a variety of stresses HuR promotes the expression of proapoptotic mRNAs, whereas others reported its regulatory effect on antiapoptotic messages. We recently showed that in response to severe stress, HuR is cleaved to generate two cleavage products (CPs), HuR-CP1 (24 kDa) and HuR-CP2 (8 kDa), by which it promotes apoptotic cell death. Here, we show that this cleavage event is dependent on protein kinase RNA (PKR). Surprisingly, although in response to the apoptotic inducer staurosporine PKR itself is not phosphorylated, PKR triggers the cleavage of HuR via its downstream effector FADD that in turn activates the caspase-8/caspase-3 pathway. This effect, however, does not require the phosphorylation of the eukaryotic translation initiation factor 2alpha. Additionally, we observed that these HuR-CPs are sufficient to trigger cell death in the absence of activation of the PKR pathway. Therefore, our results support a model whereby in response to lethal stress, PKR, without being phosphorylated, activates the FADD/caspase-8/caspase-3 pathway to trigger HuR cleavage, and the HuR-CPs are then capable of promoting apoptosis.
Collapse
Affiliation(s)
- Christopher von Roretz
- From the Biochemistry Department and Rosalind and Morris Goodman Cancer Center, McGill University, Montreal, Ontario H3G 1Y6, Canada
| | - Imed-Eddine Gallouzi
- From the Biochemistry Department and Rosalind and Morris Goodman Cancer Center, McGill University, Montreal, Ontario H3G 1Y6, Canada
| |
Collapse
|
38
|
The cleavage of HuR interferes with its transportin-2-mediated nuclear import and promotes muscle fiber formation. Cell Death Differ 2010; 17:1588-99. [PMID: 20379198 DOI: 10.1038/cdd.2010.34] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although the function of posttranscriptional processes in regulating the expression of genes involved in muscle fiber formation (myogenesis) is well accepted, the mechanisms by which these effects are mediated remain elusive. Here, we uncover such a mechanism and show that during myogenesis, a fraction of the posttranscriptional regulator human antigen R (HuR) is cleaved in a caspase-dependent manner in both cell culture and animal models. Disruption of caspase activity in cultured myoblasts or knocking out the caspase-3 gene in mice significantly reduced HuR cleavage and the cytoplasmic accumulation of HuR in muscle fibers. The non-cleavable isoform of HuR, HuRD226A, failed to reestablish the myogenic potential of HuR-depleted myoblasts. HuR cleavage generates two fragments: HuR-cleavage product 1 (HuR-CP1) (24 kDa) and HuR-CP2 (8 kDa). Here, we show that one of these fragments (HuR-CP1) binds to the HuR import factor transportin-2 (TRN2) allowing HuR to accumulate in the cytoplasm. As this cytoplasmic accumulation is required for the promyogenic function of HuR, our data support a model, whereby during the transition phase from myoblasts to myotubes, a proportion of HuR is cleaved to generate HuR-CP1. By interfering with the TRN2-mediated import of HuR, this CP helps non-cleaved HuR accumulate in the cytoplasm thus promoting myogenesis.
Collapse
|
39
|
Lai RYJ, Ljubicic V, D'souza D, Hood DA. Effect of chronic contractile activity on mRNA stability in skeletal muscle. Am J Physiol Cell Physiol 2010; 299:C155-63. [PMID: 20375275 DOI: 10.1152/ajpcell.00523.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Repeated bouts of exercise promote the biogenesis of mitochondria by multiple steps in the gene expression patterning. The role of mRNA stability in controlling the expression of mitochondrial proteins is relatively unexplored. To induce mitochondrial biogenesis, we chronically stimulated (10 Hz; 3 or 6 h/day) rat muscle for 7 days. Chronic contractile activity (CCA) increased the protein expression of PGC-1alpha, c-myc, and mitochondrial transcription factor A (Tfam) by 1.6-, 1.7- and 2.0-fold, respectively. To determine mRNA stability, we incubated total RNA with cytosolic extracts using an in vitro cell-free system. We found that the intrinsic mRNA half-lives (t(1/2)) were variable within control muscle. Peroxisome proliferator-activated receptor-gamma, coactivator-1alpha (PGC-1alpha) and Tfam mRNAs decayed more rapidly (t(1/2) = 22.7 and 31.4 min) than c-myc mRNA (t(1/2) = 99.7 min). Furthermore, CCA resulted in a differential response in degradation kinetics. After CCA, PGC-1alpha and Tfam mRNA half-lives decreased by 48% and 44%, respectively, whereas c-myc mRNA half-life was unchanged. CCA induced an elevation of both the cytosolic RNA-stabilizing human antigen R (HuR) and destabilizing AUF1 (total) by 2.4- and 1.8-fold, respectively. Increases in the p37(AUF1), p40(AUF1), and p45(AUF1) isoforms were most evident. Thus these data indicate that CCA results in accelerated turnover rates of mRNAs encoding important mitochondrial biogenesis regulators in skeletal muscle. This adaptation is likely beneficial in permitting more rapid phenotypic plasticity in response to subsequent contractile activity.
Collapse
Affiliation(s)
- Ruanne Y J Lai
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | | | | | | |
Collapse
|
40
|
The role of the nuclear transport system in cell differentiation. Semin Cell Dev Biol 2009; 20:590-9. [PMID: 19465141 DOI: 10.1016/j.semcdb.2009.05.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 04/24/2009] [Accepted: 05/15/2009] [Indexed: 11/23/2022]
Abstract
The eukaryotic cell nuclear transport system selectively mediates molecular trafficking to facilitate the regulation of cellular processes. The components of this system include diverse transport factors such as importins and nuclear pore components that are precisely organized to coordinate cellular events. A number of studies have demonstrated that the nuclear transport system is indispensible in many types of cellular responses. In particular, the nuclear transport machinery has been shown to be an important regulator of development, organogenesis, and tissue formation, wherein altered nuclear transport of key transcription factors can lead to disease. Importantly, precise switching between distinct forms of importin alpha is central to neural lineage specification, consistent with the hypothesis that importin expression can be a key mediator of cell differentiation.
Collapse
|
41
|
The RNA-binding protein Elavl1/HuR is essential for placental branching morphogenesis and embryonic development. Mol Cell Biol 2009; 29:2762-76. [PMID: 19307312 DOI: 10.1128/mcb.01393-08] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
HuR is an RNA-binding protein implicated in a diverse array of pathophysiological processes due to its effects on the posttranscriptional regulation of AU- and U-rich mRNAs. Here we reveal HuR's requirement in embryonic development through its genetic ablation. Obligatory HuR-null embryos exhibited a stage retardation phenotype and failed to survive beyond midgestation. By means of conditional transgenesis, we restricted HuR's mutation in either embryonic or endothelial compartments to demonstrate that embryonic lethality is consequent to defects in extraembryonic placenta. HuR's absence impaired the invagination of allantoic capillaries into the chorionic trophoblast layer and the differentiation of syncytiotrophoblast cells that control the morphogenesis and vascularization of the placental labyrinth and fetal support. HuR-null embryos rescued from these placental defects proceeded to subsequent developmental stages but displayed defects in skeletal ossification, fusions in limb elements, and asplenia. By coupling gene expression measurements, data meta-analysis, and HuR-RNA association assays, we identified transcription and growth factor mRNAs controlled by HuR, primarily at the posttranscriptional level, to guide morphogenesis, specification, and patterning. Collectively, our data demonstrate the dominant role of HuR in organizing gene expression programs guiding placental labyrinth morphogenesis, skeletal specification patterns, and splenic ontogeny.
Collapse
|
42
|
Meisner NC, Hintersteiner M, Seifert JM, Bauer R, Benoit RM, Widmer A, Schindler T, Uhl V, Lang M, Gstach H, Auer M. Terminal adenosyl transferase activity of posttranscriptional regulator HuR revealed by confocal on-bead screening. J Mol Biol 2008; 386:435-50. [PMID: 19109971 DOI: 10.1016/j.jmb.2008.12.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/24/2008] [Accepted: 12/08/2008] [Indexed: 01/10/2023]
Abstract
Posttranscriptional regulation and RNA metabolism have become central topics in the understanding of mammalian gene expression and cell signalling, with the 3' untranslated region emerging as the coordinating unit. The 3' untranslated region trans-acting factor Hu protein R (HuR) forms a central posttranscriptional pathway node bridging between AU-rich element-mediated processes and microRNA regulation. While (m)RNA control by HuR has been extensively characterized, the molecular mode of action still remains elusive. Here we describe the identification of the first RRM3 (RNA recognition motif 3) targeted low molecular weight HuR inhibitors from a one-bead-one-compound library screen using confocal nanoscanning. A further compound characterization revealed the presence of an ATP-binding pocket within HuR RRM3, associated with enzymatic activity. Centered around a metal-ion-coordinating DxD motif, the catalytic site mediates 3'-terminal adenosyl modification of non-polyadenylated RNA substrates by HuR. These findings suggest that HuR actively contributes to RNA modification and maturation and thereby shed an entirely new light on the role of HuR in RNA metabolism.
Collapse
|
43
|
Okada N, Ishigami Y, Suzuki T, Kaneko A, Yasui K, Fukutomi R, Isemura M. Importins and exportins in cellular differentiation. J Cell Mol Med 2008; 12:1863-71. [PMID: 18657223 PMCID: PMC4506156 DOI: 10.1111/j.1582-4934.2008.00437.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The importin/exportin transport system provides the machinery involved in nucleocytoplasmic transport. Alterations of the levels of importins and exportins may play crucial roles in development, differentiation and transformation. Employing human leukaemia HL-60 cells, we and others have revealed the differentiation-associated changes in the protein and gene expression of these factors. The recent finding that a switch to the importin-α subtype triggers neural differentiation of embryonic stem cells underscores the importance of nucleocytoplasmic transport factors in cellular events. This review focuses on current research into the roles of importins and exportins in cell differentiation.
Collapse
Affiliation(s)
- Norihisa Okada
- Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | | | | | | | | | | | | |
Collapse
|
44
|
Cammas A, Lewis SM, Vagner S, Holcik M. Post-transcriptional control of gene expression through subcellular relocalization of mRNA binding proteins. Biochem Pharmacol 2008; 76:1395-403. [PMID: 18582437 DOI: 10.1016/j.bcp.2008.05.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 04/28/2008] [Accepted: 05/16/2008] [Indexed: 11/15/2022]
Abstract
Eukaryotic cells have developed multiple mechanisms to respond to different physiological cues, such as cellular stress, which allow the cells to adapt themselves to their new environment. The regulation of post-transcriptional gene expression is an important component of the cellular stress response and is mediated by mRNA binding proteins (mRBPs). Recently, several studies have shown that regulated subcellular localization of mRBPs upon diverse stimuli (such as cellular stress) provides an additional level of regulation for gene expression.
Collapse
|
45
|
Mazroui R, Di Marco S, Clair E, von Roretz C, Tenenbaum SA, Keene JD, Saleh M, Gallouzi IE. Caspase-mediated cleavage of HuR in the cytoplasm contributes to pp32/PHAP-I regulation of apoptosis. ACTA ACUST UNITED AC 2008; 180:113-27. [PMID: 18180367 PMCID: PMC2213623 DOI: 10.1083/jcb.200709030] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The RNA-binding protein HuR affects cell fate by regulating the stability and/or the translation of messenger RNAs that encode cell stress response proteins. In this study, we delineate a novel regulatory mechanism by which HuR contributes to stress-induced cell death. Upon lethal stress, HuR translocates into the cytoplasm by a mechanism involving its association with the apoptosome activator pp32/PHAP-I. Depleting the expression of pp32/PHAP-I by RNA interference reduces both HuR cytoplasmic accumulation and the efficiency of caspase activation. In the cytoplasm, HuR undergoes caspase-mediated cleavage at aspartate 226. This cleavage activity is significantly reduced in the absence of pp32/PHAP-I. Substituting aspartate 226 with an alanine creates a noncleavable isoform of HuR that, when overexpressed, maintains its association with pp32/PHAP-I and delays the apoptotic response. Thus, we propose a model in which HuR association with pp32/PHAP-I and its caspase-mediated cleavage constitutes a regulatory step that contributes to an amplified apoptotic response.
Collapse
Affiliation(s)
- Rachid Mazroui
- Department of Biochemistry, McGill University Health Center, McGill University, Montreal, Quebec H3G 146, Canada
| | | | | | | | | | | | | | | |
Collapse
|