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Freire-Benéitez V, Pomella N, Millner TO, Dumas AA, Niklison-Chirou MV, Maniati E, Wang J, Rajeeve V, Cutillas P, Marino S. Elucidation of the BMI1 interactome identifies novel regulatory roles in glioblastoma. NAR Cancer 2021; 3:zcab009. [PMID: 34316702 PMCID: PMC8210184 DOI: 10.1093/narcan/zcab009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/27/2021] [Accepted: 02/28/2021] [Indexed: 11/13/2022] Open
Abstract
Glioblastoma (GBM) is the most common and aggressive intrinsic brain tumour in adults. Epigenetic mechanisms controlling normal brain development are often dysregulated in GBM. Among these, BMI1, a structural component of the Polycomb Repressive Complex 1 (PRC1), which promotes the H2AK119ub catalytic activity of Ring1B, is upregulated in GBM and its tumorigenic role has been shown in vitro and in vivo. Here, we have used protein and chromatin immunoprecipitation followed by mass spectrometry (MS) analysis to elucidate the protein composition of PRC1 in GBM and transcriptional silencing of defining interactors in primary patient-derived GIC lines to assess their functional impact on GBM biology. We identify novel regulatory functions in mRNA splicing and cholesterol transport which could represent novel targetable mechanisms in GBM.
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Affiliation(s)
- Verónica Freire-Benéitez
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
| | - Nicola Pomella
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
| | - Thomas O Millner
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
| | - Anaëlle A Dumas
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
| | - Maria Victoria Niklison-Chirou
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
| | - Eleni Maniati
- Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6AS UK
| | - Jun Wang
- Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6AS UK
| | - Vinothini Rajeeve
- Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6AS UK
| | - Pedro Cutillas
- Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6AS UK
| | - Silvia Marino
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 2AT, London, UK
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Galmiche A, Fueller J. RAF kinases and mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1256-62. [PMID: 17442414 DOI: 10.1016/j.bbamcr.2006.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 10/19/2006] [Accepted: 10/20/2006] [Indexed: 01/29/2023]
Abstract
Over the past decade, several investigators reported that a fraction of the RAF kinases are recruited to the mitochondria. Although we are still far from a global understanding of the molecular consequences of RAF translocation on mitochondrial physiology and metabolism, the recent description of some molecular interactions that are established by C-RAF in this organelle, principally with the proteins Bcl-2 and Bag-1, provides some clues. Here, we discuss the possible contribution of RAF targeting to mitochondria to their modulation of apoptosis signaling, as well as to this organelle's physiology. In addition, we discuss the possible modulation of the mitochondrial metabolism by RAF oncogenes in the context of cancer.
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Affiliation(s)
- Antoine Galmiche
- Institut für Medizinische Strahlenkunde und Zellforschung (MSZ), University of Würzburg, D-97078 Würzburg, Germany.
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Fan S, Goto K, Chen G, Morinaga H, Nomura M, Okabe T, Nawata H, Yanase T. Identification of the functional domains of ANT-1, a novel coactivator of the androgen receptor. Biochem Biophys Res Commun 2006; 341:192-201. [PMID: 16414017 DOI: 10.1016/j.bbrc.2005.12.167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Accepted: 12/16/2005] [Indexed: 11/19/2022]
Abstract
Previously, we identified a transcriptional coactivator for the activation function-1 (AF-1) domain of the human androgen receptor (AR) and designated it androgen receptor N-terminal domain transactivating protein-1 (ANT-1). This coactivator, which contains multiple tetratricopeptide repeat (TPR) motifs from amino acid (aa) 294, is identical to a component of U5 small nuclear ribonucleoprotein particles and binds specifically to the AR or glucocorticoid receptor. Here, we identified four distinct functional domains. The AR-AF-1-binding domain, which bound to either aa 180-360 or 360-532 in AR-AF-1, clearly overlapped with TAU-1 and TAU-5. This domain and the subnuclear speckle formation domain in ANT-1 were assigned within the TPR motifs, while the transactivating and nuclear localization signal domains resided within the N-terminal sequence. The existence of these functional domains may further support the idea that ANT-1 can function as an AR-AF-1-specific coactivator while mediating a transcription-splicing coupling.
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Affiliation(s)
- Shuli Fan
- Department of Medicine and Bioregulatory Science (3rd Department of Internal Medicine), Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
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Goto K, Zhao Y, Saito M, Tomura A, Morinaga H, Nomura M, Okabe T, Yanase T, Takayanagi R, Nawata H. Activation function-1 domain of androgen receptor contributes to the interaction between two distinct subnuclear compartments. J Steroid Biochem Mol Biol 2003; 85:201-8. [PMID: 12943705 DOI: 10.1016/s0960-0760(03)00196-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The nucleus contains different sets of functional compartments often called "speckles". The splicing factor compartment (SFC) has been speculated to consist of SFs and transcription factors, which thus make transcription-splicing coupling possible at the periphery of SFC. Androgen receptor (AR), as well as glucocorticoid receptor (GR), is unique since most, if not all, of its activities are mediated via the constitutive activity of the activation function-1 (AF-1) function. Transcriptionally active AR produces 250-400 subnuclear fine speckles11 shared with GR or estrogen receptor (ER), which colocalize with chiefly activation function-2 (AF-2)-interacting p160 family- or CBP-related speckles. We herein report the isolation of ANT-1 (AR N-terminal domain (NTD) transactivating protein-1) enhancing autonomous AF-1 transactivation function of AR or GR, but not of estrogen receptor alpha (ERalpha). The ANT-1 was identical to a binding protein of human splicing factor U5 snRNP (U5 snRNP-associated protein). ANT-1 was compartmentalized into 15-20 coarse SFC speckles which were spatially distinct from but surrounded by the AR compartments. Our results suggest that ANT-1 may play a key role in the molecular interaction between two spatially distinct subnuclear compartments in a receptor-specific fashion, and thereby induce the strong autonomous transactivation functions either of AR- or GR-AF-1.
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Affiliation(s)
- Kiminobu Goto
- Department of Medicine and Bioregulatory Science (3rd Department of Internal Medicine), Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
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5
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Zhao Y, Goto K, Saitoh M, Yanase T, Nomura M, Okabe T, Takayanagi R, Nawata H. Activation function-1 domain of androgen receptor contributes to the interaction between subnuclear splicing factor compartment and nuclear receptor compartment. Identification of the p102 U5 small nuclear ribonucleoprotein particle-binding protein as a coactivator for the receptor. J Biol Chem 2002; 277:30031-9. [PMID: 12039962 DOI: 10.1074/jbc.m203811200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the androgen receptor (AR), most of its transactivation activity is mediated via the activation function-1 (AF-1). By employing yeast two-hybrid assay, we isolated a cDNA sequence encoding a protein binding to AR-AF-1. This protein, named ANT-1 (AR N-terminal domain transactivating protein-1), enhanced the ligand-independent autonomous AF-1 transactivation function of AR or glucocorticoid receptor but did not enhance that of estrogen receptor alpha. In contrast, the ANT-1 did not enhance any ligand-dependent AF-2 activities. Furthermore, the ligand-independent interaction between AR-AF-1 and ANT-1 was confirmed in vivo and in vitro. The ANT-1 sequence was identical to that of a protein that binds to U5 small nuclear ribonucleoprotein particle, a human homologue of yeast splicing factor Prp6p, involved in spliceosome. ANT-1 was compartmentalized into 20-40 coarse splicing factor compartment speckles against the background of the diffuse reticular distribution. AR colocalized with ANT-1 only in the diffusely distributed area, whereas the ANT-1 speckles were spatially distinct from but surrounded by the AR compartments. The active gene transcription has been shown to couple simultaneously with pre-mRNA processing at the periphery of the splicing factor compartment. The molecular interaction between two spatially distinct subnuclear compartments mediated by ANT-1 may therefore recruit AR into the transcription-splicing-coupling machinery.
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Affiliation(s)
- Yue Zhao
- Department of Medicine and Bioregulatory Science (3rd Department of Internal Medicine), Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
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Dellaire G, Makarov EM, Cowger JJM, Longman D, Sutherland HGE, Lührmann R, Torchia J, Bickmore WA. Mammalian PRP4 kinase copurifies and interacts with components of both the U5 snRNP and the N-CoR deacetylase complexes. Mol Cell Biol 2002; 22:5141-56. [PMID: 12077342 PMCID: PMC139773 DOI: 10.1128/mcb.22.14.5141-5156.2002] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A growing body of evidence supports the coordination of pre-mRNA processing and transcriptional regulation. We demonstrate here that mammalian PRP4 kinase (PRP4K) is associated with complexes involved in both of these processes. PRP4K is implicated in pre-mRNA splicing as the homologue of the Schizosaccharomyces pombe pre-mRNA splicing kinase Prp4p, and it is enriched in SC35-containing nuclear splicing speckles. RNA interference of Caenorhabditis elegans PRP4K indicates that it is essential in metazoans. In support of a role for PRP4K in pre-mRNA splicing, we identified PRP6, SWAP, and pinin as interacting proteins and demonstrated that PRP4K is a U5 snRNP-associated kinase. In addition, BRG1 and N-CoR, components of nuclear hormone coactivator and corepressor complexes, also interact with PRP4K. PRP4K coimmunoprecipitates with N-CoR, BRG1, pinin, and PRP6, and we present data suggesting that PRP6 and BRG1 are substrates of this kinase. Lastly, PRP4K, BRG1, and PRP6 can be purified as components of the N-CoR-2 complex, and affinity-purified PRP4K/N-CoR complexes exhibit deacetylase activity. We suggest that PRP4K is an essential kinase that, in association with the both U5 snRNP and N-CoR deacetylase complexes, demonstrates a possible coordination of pre-mRNA splicing with chromatin remodeling events involved in transcriptional regulation.
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Affiliation(s)
- Graham Dellaire
- MRC-Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, Scotland, UK
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Abstract
The annotation of the human genome indicates the surprisingly low number of approximately 40,000 genes. However, the estimated number of proteins encoded by these genes is two to three orders of magnitude higher. The ability to unambiguously identify the proteins is a prerequisite for their functional investigation. As proteins derived from the same gene can be largely identical, and might differ only in small but functionally relevant details, protein identification tools must not only identify a large number of proteins but also be able to differentiate between close relatives. This information can be generated by mass spectrometry, an approach that identifies proteins by partial analysis of their digestion-derived peptides. Information gleaned from databases fills in the missing sequence information. Because both sequence databases and experimental data are limited, a certain ambiguity often remains concerning which sequence variant(s) and modification(s) are present. As the common denominator of all the isoforms is a gene, in our opinion, it would be more accurate to state that a product of this particular gene rather than a certain protein has been identified by mass spectrometry.
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Affiliation(s)
- Juri Rappsilber
- Protein Interaction Laboratory, Center of Experimental Bioinformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 M Odense, Denmark.
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NISHIKIMI A, MUKAI J, IKEDA S, YAMADA M. Nuclear Translocation of a Pre-mRNA Splicing Factor, p100prp1/zer1/prp6, in Mouse 1-cell Embryos. J Reprod Dev 2002. [DOI: 10.1262/jrd.48.257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Akihiko NISHIKIMI
- Laboratory of Reproductive Physiology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University
- Department of Basic Gerontology, National Institute for Longevity Science
| | - Jiro MUKAI
- Laboratory of Reproductive Physiology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University
| | - Shuntaro IKEDA
- Laboratory of Reproductive Physiology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University
| | - Masayasu YAMADA
- Laboratory of Reproductive Physiology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University
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Rappsilber J, Ajuh P, Lamond AI, Mann M. SPF30 is an essential human splicing factor required for assembly of the U4/U5/U6 tri-small nuclear ribonucleoprotein into the spliceosome. J Biol Chem 2001; 276:31142-50. [PMID: 11331295 DOI: 10.1074/jbc.m103620200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spliceosome assembly involves the sequential recruitment of small nuclear ribonucleoproteins (snRNPs) onto a pre-mRNA substrate. Although several non-snRNP proteins function during the binding of U1 and U2 snRNPs, little is known about the subsequent binding of the U4/U5/U6 tri-snRNP. A recent proteomic analysis of the human spliceosome identified SPF30 (Neubauer, G., King, A., Rappsilber, J., Calvio, C., Watson, M., Ajuh, P., Sleeman, J., Lamond, A., and Mann, M. (1998) Nat. Genet. 20, 46-50), a homolog of the survival of motor neurons (SMN) protein, as a spliceosome factor. We show here that SPF30 is a nuclear protein that associates with both U4/U5/U6 and U2 snRNP components. In the absence of SPF30, the preformed tri-snRNP fails to assemble into the spliceosome. Mass spectrometric analysis shows that a recombinant glutathione S-transferase-SPF30 fusion protein associates with complexes containing core Sm and U4/U5/U6 tri-snRNP proteins when added to HeLa nuclear extract, most strongly to U4/U6-90. The data indicate that SPF30 is an essential human splicing factor that may act to dock the U4/U5/U6 tri-snRNP to the A complex during spliceosome assembly or, alternatively, may act as a late assembly factor in both the tri-snRNP and the A-complex.
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Affiliation(s)
- J Rappsilber
- Protein Interaction Laboratory, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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