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Chauhan W, Sudharshan SJ, Kafle S, Zennadi R. SnoRNAs: Exploring Their Implication in Human Diseases. Int J Mol Sci 2024; 25:7202. [PMID: 39000310 PMCID: PMC11240930 DOI: 10.3390/ijms25137202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/16/2024] Open
Abstract
Small nucleolar RNAs (snoRNAs) are earning increasing attention from research communities due to their critical role in the post-transcriptional modification of various RNAs. These snoRNAs, along with their associated proteins, are crucial in regulating the expression of a vast array of genes in different human diseases. Primarily, snoRNAs facilitate modifications such as 2'-O-methylation, N-4-acetylation, and pseudouridylation, which impact not only ribosomal RNA (rRNA) and their synthesis but also different RNAs. Functionally, snoRNAs bind with core proteins to form small nucleolar ribonucleoproteins (snoRNPs). These snoRNAs then direct the protein complex to specific sites on target RNA molecules where modifications are necessary for either standard cellular operations or the regulation of pathological mechanisms. At these targeted sites, the proteins coupled with snoRNPs perform the modification processes that are vital for controlling cellular functions. The unique characteristics of snoRNAs and their involvement in various non-metabolic and metabolic diseases highlight their potential as therapeutic targets. Moreover, the precise targeting capability of snoRNAs might be harnessed as a molecular tool to therapeutically address various disease conditions. This review delves into the role of snoRNAs in health and disease and explores the broad potential of these snoRNAs as therapeutic agents in human pathologies.
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Affiliation(s)
| | | | | | - Rahima Zennadi
- Department of Physiology, University of Tennessee Health Science Center, 71 S. Manassas St., Memphis, TN 38103, USA; (W.C.); (S.S.); (S.K.)
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Torii T, Miyamoto Y, Yamauchi J. Myelination by signaling through Arf guanine nucleotide exchange factor. J Neurochem 2024. [PMID: 38894552 DOI: 10.1111/jnc.16141] [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: 03/11/2024] [Revised: 05/19/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024]
Abstract
During myelination, large quantities of proteins are synthesized and transported from the endoplasmic reticulum (ER)-trans-Golgi network (TGN) to their appropriate locations within the intracellular region and/or plasma membrane. It is widely believed that oligodendrocytes uptake neuronal signals from neurons to regulate the endocytosis- and exocytosis-mediated intracellular trafficking of major myelin proteins such as myelin-associated glycoprotein (MAG) and proteolipid protein 1 (PLP1). The small GTPases of the adenosine diphosphate (ADP) ribosylation factor (Arf) family constitute a large group of signal transduction molecules that act as regulators for intracellular signaling, vesicle sorting, or membrane trafficking in cells. Studies on mice deficient in Schwann cell-specific Arfs-related genes have revealed abnormal myelination formation in peripheral nerves, indicating that Arfs-mediated signaling transduction is required for myelination in Schwann cells. However, the complex roles in these events remain poorly understood. This review aims to provide an update on signal transduction, focusing on Arf and its activator ArfGEF (guanine nucleotide exchange factor for Arf) in oligodendrocytes and Schwann cells. Future studies are expected to provide important information regarding the cellular and physiological processes underlying the myelination of oligodendrocytes and Schwann cells and their function in modulating neural activity.
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Affiliation(s)
- Tomohiro Torii
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Yuki Miyamoto
- Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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3
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Pei J, Zhang J, Wang XD, Kim C, Yu Y, Cong Q. Impact of Asp/Glu-ADP-ribosylation on protein-protein interaction and protein function. Proteomics 2023; 23:e2200083. [PMID: 36453556 PMCID: PMC10362910 DOI: 10.1002/pmic.202200083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/12/2022] [Accepted: 11/10/2022] [Indexed: 12/04/2022]
Abstract
PARylation plays critical role in regulating multiple cellular processes such as DNA damage response and repair, transcription, RNA processing, and stress response. More than 300 human proteins have been found to be modified by PARylation on acidic residues, that is, Asp (D) and Glu (E). We used the deep-learning tool AlphaFold to predict protein-protein interactions (PPIs) and their interfaces for these proteins based on coevolution signals from joint multiple sequence alignments (MSAs). AlphaFold predicted 260 confident PPIs involving PARylated proteins, and about one quarter of these PPIs have D/E-PARylation sites in their predicted PPI interfaces. AlphaFold predictions offer novel insights into the mechanisms of PARylation regulations by providing structural details of the PPI interfaces. D/E-PARylation sites have a preference to occur in coil regions and disordered regions, and PPI interfaces containing D/E-PARylation sites tend to occur between short linear sequence motifs in disordered regions and globular domains. The hub protein PCNA is predicted to interact with more than 20 proteins via the common PIP box motif and the structurally variable flanking regions. D/E-PARylation sites were found in the interfaces of key components of the RNA transcription and export complex, the SF3a spliceosome complex, and H/ACA and C/D small nucleolar ribonucleoprotein complexes, suggesting that systematic PARylation have a profound effect in regulating multiple RNA-related processes such as RNA nuclear export, splicing, and modification. Finally, PARylation of SUMO2 could modulate its interaction with CHAF1A, thereby representing a potential mechanism for the cross-talk between PARylation and SUMOylation in regulation of chromatin remodeling.
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Affiliation(s)
- Jimin Pei
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jing Zhang
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xu-Dong Wang
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Chiho Kim
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Yonghao Yu
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Qian Cong
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
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4
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Abstract
RNA-binding proteins are important regulators of RNA metabolism and are of critical importance in all steps of the gene expression cascade. The role of aberrantly expressed RBPs in human disease is an exciting research field and the potential application of RBPs as a therapeutic target or a diagnostic marker represents a fast-growing area of research.Aberrant overexpression of the human RNA-binding protein La has been found in various cancer entities including lung, cervical, head and neck, and chronic myelogenous leukaemia. Cancer-associated La protein supports tumour-promoting processes such as proliferation, mobility, invasiveness and tumour growth. Moreover, the La protein maintains the survival of cancer cells by supporting an anti-apoptotic state that may cause resistance to chemotherapeutic therapy.The human La protein represents a multifunctional post-translationally modified RNA-binding protein with RNA chaperone activity that promotes processing of non-coding precursor RNAs but also stimulates the translation of selective messenger RNAs encoding tumour-promoting and anti-apoptotic factors. In our model, La facilitates the expression of those factors and helps cancer cells to cope with cellular stress. In contrast to oncogenes, able to initiate tumorigenesis, we postulate that the aberrantly elevated expression of the human La protein contributes to the non-oncogenic addiction of cancer cells. In this review, we summarize the current understanding about the implications of the RNA-binding protein La in cancer progression and therapeutic resistance. The concept of exploiting the RBP La as a cancer drug target will be discussed.
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Affiliation(s)
- Gunhild Sommer
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
| | - Tilman Heise
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
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Sztul E, Chen PW, Casanova JE, Cherfils J, Dacks JB, Lambright DG, Lee FJS, Randazzo PA, Santy LC, Schürmann A, Wilhelmi I, Yohe ME, Kahn RA. ARF GTPases and their GEFs and GAPs: concepts and challenges. Mol Biol Cell 2019; 30:1249-1271. [PMID: 31084567 PMCID: PMC6724607 DOI: 10.1091/mbc.e18-12-0820] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/26/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022] Open
Abstract
Detailed structural, biochemical, cell biological, and genetic studies of any gene/protein are required to develop models of its actions in cells. Studying a protein family in the aggregate yields additional information, as one can include analyses of their coevolution, acquisition or loss of functionalities, structural pliability, and the emergence of shared or variations in molecular mechanisms. An even richer understanding of cell biology can be achieved through evaluating functionally linked protein families. In this review, we summarize current knowledge of three protein families: the ARF GTPases, the guanine nucleotide exchange factors (ARF GEFs) that activate them, and the GTPase-activating proteins (ARF GAPs) that have the ability to both propagate and terminate signaling. However, despite decades of scrutiny, our understanding of how these essential proteins function in cells remains fragmentary. We believe that the inherent complexity of ARF signaling and its regulation by GEFs and GAPs will require the concerted effort of many laboratories working together, ideally within a consortium to optimally pool information and resources. The collaborative study of these three functionally connected families (≥70 mammalian genes) will yield transformative insights into regulation of cell signaling.
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Affiliation(s)
- Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, MA 01267
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS and Ecole Normale Supérieure Paris-Saclay, 94235 Cachan, France
| | - Joel B. Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - David G. Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Amherst, MA 01605
| | - Fang-Jen S. Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | | | - Lorraine C. Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Annette Schürmann
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Ilka Wilhelmi
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Marielle E. Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050
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Jun YW, Lee SH, Shim J, Lee JA, Lim CS, Kaang BK, Jang DJ. Dual roles of the N-terminal coiled-coil domain of anAplysiasec7 protein: homodimer formation and nuclear export. J Neurochem 2016; 139:1102-1112. [DOI: 10.1111/jnc.13875] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/13/2016] [Accepted: 10/12/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Yong-Woo Jun
- Department of Ecological Science; College of Ecology and Environment; Kyungpook National University; Sangju-si Gyeongsangbuk-do Korea
| | - Seung-Hee Lee
- Department of Biological Sciences; Korea Institute of Science and Technology (KAIST); Daejeon Korea
| | - Jaehoon Shim
- Department of Biological Sciences; College of Natural Sciences; Seoul National University; Gwanak-gu Seoul Korea
| | - Jin-A Lee
- Department of Biotechnology and Biological Science; College of Life Science and Nano Technology; Hannam University; Yuseong-daero; Yuseong-gu Daejeon Korea
| | - Chae-Seok Lim
- Department of Biological Sciences; College of Natural Sciences; Seoul National University; Gwanak-gu Seoul Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences; College of Natural Sciences; Seoul National University; Gwanak-gu Seoul Korea
| | - Deok-Jin Jang
- Department of Ecological Science; College of Ecology and Environment; Kyungpook National University; Sangju-si Gyeongsangbuk-do Korea
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7
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Differential expression and accumulation of 14-3-3 paralogs in 3T3-L1 preadipocytes and differentiated cells. Biochem Biophys Rep 2016; 7:106-112. [PMID: 28955896 PMCID: PMC5613295 DOI: 10.1016/j.bbrep.2016.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/16/2016] [Accepted: 05/27/2016] [Indexed: 11/22/2022] Open
Abstract
The 14-3-3 protein family interacts with more than 2000 different proteins in mammals, as a result of its specific phospho-serine/phospho-threonine binding activity. Seven paralogs are strictly conserved in mammalian species. Here, we show that during adipogenic differentiation of 3T3-L1 preadipocytes, the level of each 14-3-3 protein paralog is regulated independently. For instance 14-3-3β, γ, and η protein levels are increased compared to untreated cells. In contrast, 14-3-3ε protein levels decreased after differentiation while others remained constant. In silico analysis of the promoter region of each gene showed differences that explain the results obtained at mRNA and protein levels. 14-3-3 paralogs are regulated independently during 3T3-L1 adipogenesis. 14-3-3β, γ, and η are specifically accumulated during adipogenesis. Promoter sequence differences may explain this specific regulation.
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Rodriguez-Corona U, Sobol M, Rodriguez-Zapata LC, Hozak P, Castano E. Fibrillarin from Archaea to human. Biol Cell 2015; 107:159-74. [PMID: 25772805 DOI: 10.1111/boc.201400077] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 03/05/2015] [Indexed: 12/19/2022]
Abstract
Fibrillarin is an essential protein that is well known as a molecular marker of transcriptionally active RNA polymerase I. Fibrillarin methyltransferase activity is the primary known source of methylation for more than 100 methylated sites involved in the first steps of preribosomal processing and required for structural ribosome stability. High expression levels of fibrillarin have been observed in several types of cancer cells, particularly when p53 levels are reduced, because p53 is a direct negative regulator of fibrillarin transcription. Here, we show fibrillarin domain conservation, structure and interacting molecules in different cellular processes as well as with several viral proteins during virus infection.
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Affiliation(s)
- Ulises Rodriguez-Corona
- Unidad de Bioquímica y Biología molecular de plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Mérida, Yucatan, Mexico
| | - Margarita Sobol
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic
| | - Luis Carlos Rodriguez-Zapata
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Mérida, Yucatan, Mexico
| | - Pavel Hozak
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic
| | - Enrique Castano
- Unidad de Bioquímica y Biología molecular de plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Mérida, Yucatan, Mexico
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9
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Regulating the large Sec7 ARF guanine nucleotide exchange factors: the when, where and how of activation. Cell Mol Life Sci 2014; 71:3419-38. [PMID: 24728583 DOI: 10.1007/s00018-014-1602-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/27/2014] [Accepted: 03/03/2014] [Indexed: 10/25/2022]
Abstract
Eukaryotic cells require selective sorting and transport of cargo between intracellular compartments. This is accomplished at least in part by vesicles that bud from a donor compartment, sequestering a subset of resident protein "cargos" destined for transport to an acceptor compartment. A key step in vesicle formation and targeting is the recruitment of specific proteins that form a coat on the outside of the vesicle in a process requiring the activation of regulatory GTPases of the ARF family. Like all such GTPases, ARFs cycle between inactive, GDP-bound, and membrane-associated active, GTP-bound, conformations. And like most regulatory GTPases the activating step is slow and thought to be rate limiting in cells, requiring the use of ARF guanine nucleotide exchange factor (GEFs). ARF GEFs are characterized by the presence of a conserved, catalytic Sec7 domain, though they also contain motifs or additional domains that confer specificity to localization and regulation of activity. These domains have been used to define and classify five different sub-families of ARF GEFs. One of these, the BIG/GBF1 family, includes three proteins that are each key regulators of the secretory pathway. GEF activity initiates the coating of nascent vesicles via the localized generation of activated ARFs and thus these GEFs are the upstream regulators that define the site and timing of vesicle production. Paradoxically, while we have detailed molecular knowledge of how GEFs activate ARFs, we know very little about how GEFs are recruited and/or activated at the right time and place to initiate transport. This review summarizes the current knowledge of GEF regulation and explores the still uncertain mechanisms that position GEFs at "budding ready" membrane sites to generate highly localized activated ARFs.
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10
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Kim JH, Kim TW, Kim SJ. Downregulation of ARFGEF1 and CAMK2B by promoter hypermethylation in breast cancer cells. BMB Rep 2011; 44:523-8. [PMID: 21871176 DOI: 10.5483/bmbrep.2011.44.8.523] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
To identify novel genes that are regulated by promoter methylation, a combinational approach involving in silico mining followed by molecular assay was performed. From the expression microarray data registered in the European bioinformatics institute (EBI), genes showing downregulation in breast cancer cells were initially screened and then selected by e-Northern analysis using the Unigene database. A series of these in silico methods identified CAMK2B and ARFGEF1 as candidates, and the two genes were revealed to be hypermethylated in breast cancer cell lines and hypomethylated in normal breast cell lines. Additionally, cancer cell lines showed downregulated expression of these genes. Furthermore, treatment of the cancer cell lines with a demethylation agent, 5-Aza-2'-deoxycytidine, recovered expression of CAMK2B and ARFGEF1, implying that hypermethyaltion silenced gene activity in cancer cells. Taken together, promoter methylations of CAMK2B and ARFGEF1 are novel epigenetic markers identified in breast cancer cell lines and can be utilized for the application to clinical cancer tissues.
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Affiliation(s)
- Ju Hee Kim
- Department of Life Science, Dongguk University-Seoul, Korea
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11
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Effects of brefeldin A-inhibited guanine nucleotide-exchange (BIG) 1 and KANK1 proteins on cell polarity and directed migration during wound healing. Proc Natl Acad Sci U S A 2011; 108:19228-33. [PMID: 22084092 DOI: 10.1073/pnas.1117011108] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Brefeldin A-inhibited guanine nucleotide-exchange protein (BIG) 1 activates class I ADP ribosylation factors (ARFs) by accelerating the replacement of bound GDP with GTP to initiate recruitment of coat proteins for membrane vesicle formation. Among proteins that interact with BIG1, kinesin family member 21A (KIF21A), a plus-end-directed motor protein, moves cargo away from the microtubule-organizing center (MTOC) on microtubules. Because KANK1, a protein containing N-terminal KN, C-terminal ankyrin-repeat, and intervening coiled-coil domains, has multiple actions in cells and also interacts with KIF21A, we explored a possible interaction between it and BIG1. We obtained evidence for a functional and physical association between these proteins, and found that the effects of BIG1 and KANK1 depletion on cell migration in wound-healing assays were remarkably similar. Treatment of cells with BIG1- or KANK1-specific siRNA interfered significantly with directed cell migration and initial orientation of Golgi/MTOC toward the leading edge, which was not mimicked by KIF21A depletion. Although colocalization of overexpressed KANK1 and endogenous BIG1 in HeLa cells was not clear microscopically, their reciprocal immunoprecipitation (IP) is compatible with the presence of small percentages of each protein in the same complexes. Depletion or overexpression of BIG1 protein appeared not to affect KANK1 distribution. Our data identify actions of both BIG1 and KANK1 in regulating cell polarity during directed migration; these actions are consistent with the presence of both BIG1 and KANK1 in dynamic multimolecular complexes that maintain Golgi/MTOC orientation, differ from those that might contain all three proteins (BIG1, KIF21A, and KANK1), and function in directed transport along microtubules.
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12
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Boulay PL, Schlienger S, Lewis-Saravalli S, Vitale N, Ferbeyre G, Claing A. ARF1 controls proliferation of breast cancer cells by regulating the retinoblastoma protein. Oncogene 2011; 30:3846-61. [PMID: 21478909 DOI: 10.1038/onc.2011.100] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ADP-ribosylation factors (ARFs) 1 and 6 are small GTP-binding proteins, highly expressed and activated in several breast cancer cell lines and are associated with enhanced migration and invasiveness. In this study, we report that ARF1 has a critical role in cell proliferation. Depletion of this GTPase or expression of a dominant negative form, which both resulted in diminished ARF1 activity, led to sustained cell-growth arrest. This cellular response was associated with the induction of senescent markers in highly invasive breast cancer cells as well as in control mammary epithelial cells by a mechanism regulating retinoblastoma protein (pRB) function. When examining the role of ARF1, we found that this GTPase was highly activated in normal proliferative conditions, and that a limited amount could be found in the nucleus, associated with the chromatin of MDA-MB-231 cells. However, when cells were arrested in the G(0)/G(1) phase or transfected with a dominant negative form of ARF1, the total level of activated ARF1 was markedly reduced and the GTPase significantly enriched in the chromatin. Using biochemical approaches, we demonstrated that the GDP-bound form of ARF1 directly interacted with pRB, but not other members of this family of proteins. In addition, depletion of ARF1 or expression of ARF1T(31)N resulted in the constitutive association of pRB and E2F1, thereby stabilizing the interaction of E2F1 as well as pRB at endogenous sites of target gene promoters, preventing expression of E2F target genes, such as cyclin D1, Mcm6 and E2F1, important for cell-cycle progression. These novel findings provide direct physiological and molecular evidence for the role of ARF1 in controlling cell proliferation, dependent on its ability to regulate pRB/E2F1 activity and gene expression for enhanced proliferation and breast cancer progression.
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Affiliation(s)
- P-L Boulay
- Department of Pharmacology, University of Montreal, Québec, Canada
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13
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Structurally Constrained Residues Outside the Binding Motif Are Essential in the Interaction of 14-3-3 and Phosphorylated Partner. J Mol Biol 2011; 406:552-7. [DOI: 10.1016/j.jmb.2010.12.043] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/14/2010] [Accepted: 12/29/2010] [Indexed: 11/20/2022]
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14
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Garcia MC, Williams J, Johnson K, Olden K, Roberts JD. Arachidonic acid stimulates formation of a novel complex containing nucleolin and RhoA. FEBS Lett 2011; 585:618-22. [PMID: 21281639 PMCID: PMC3089762 DOI: 10.1016/j.febslet.2011.01.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Revised: 12/21/2010] [Accepted: 01/13/2011] [Indexed: 10/18/2022]
Abstract
Arachidonic acid (AA) stimulates cell adhesion through a p38 mitogen activated protein kinase-mediated RhoA signaling pathway. Here we report that a proteomic screen following AA-treatment identified nucleolin, a multifunctional nucleolar protein, in a complex with the GTPase, RhoA, that also included the Rho kinase, ROCK. AA-stimulated cell adhesion was inhibited by expression of nucleolin-targeted shRNA and formation of the multiprotein complex was blocked by expression of dominant-negative RhoA. AA-treatment also induced ROCK-dependent serine phosphorylation of nucleolin and translocation of nucleolin from the nucleus to the cytoplasm, where it appeared to co-localize with RhoA. These data suggest the existence of a new signaling pathway through which the location and post-translational state of nucleolin are modulated.
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Affiliation(s)
- Melissa C. Garcia
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Jason Williams
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Katina Johnson
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Kenneth Olden
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - John D. Roberts
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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15
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Haffner MC, Aryee MJ, Toubaji A, Esopi DM, Albadine R, Gurel B, Isaacs WB, Bova GS, Liu W, Xu J, Meeker AK, Netto G, De Marzo AM, Nelson WG, Yegnasubramanian S. Androgen-induced TOP2B-mediated double-strand breaks and prostate cancer gene rearrangements. Nat Genet 2010; 42:668-75. [PMID: 20601956 PMCID: PMC3157086 DOI: 10.1038/ng.613] [Citation(s) in RCA: 466] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 06/02/2010] [Indexed: 12/21/2022]
Abstract
DNA double strand breaks (DSB) can lead to development of genomic rearrangements, which are hallmarks of cancer. TMPRSS2-ERG gene fusions in prostate cancer (PCa) are among the most common genomic rearrangements observed in human cancer. We show that androgen signaling promotes co-recruitment of androgen receptor (AR) and topoisomerase II beta (TOP2B) to sites of TMPRSS2-ERG genomic breakpoints, triggering recombinogenic TOP2B-mediated DSB. Furthermore, androgen stimulation resulted in de novo production of TMPRSS2-ERG fusion transcripts in a process requiring TOP2B and components of DSB repair machinery. Finally, unlike normal prostate epithelium, prostatic intraepithelial neoplasia (PIN) cells showed strong co-expression of AR and TOP2B. These findings implicate androgen-induced TOP2B-mediated DSB in generating TMPRSS2-ERG rearrangements.
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Affiliation(s)
- Michael C Haffner
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland, USA
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Nalabothula N, Indig FE, Carrier F. The Nucleolus Takes Control of Protein Trafficking Under Cellular Stress. MOLECULAR AND CELLULAR PHARMACOLOGY 2010; 2:203-212. [PMID: 21499571 PMCID: PMC3076688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The nucleolus is a highly dynamic nuclear substructure that was originally described as the site of ribosome biogenesis. The advent of proteomic analysis has now allowed the identification of over 4500 nucleolus associated proteins with only about 30% of them associated with ribogenesis (1). The great number of nucleolar proteins not associated with traditionally accepted nucleolar functions indicates a role for the nucleolus in other cellular functions such as mitosis, cell-cycle progression, cell proliferation and many forms of stress response including DNA repair (2). A number of recent reviews have addressed the pivotal role of the nucleolus in the cellular stress response (1, 3, 4). Here, we will focus on the role of Nucleolin and Nucleophosmin, two major components of the nucleolus, in response to genotoxic stress. Due to space constraint only a limited number of studies are cited. We thus apologize to all our colleagues whose works are not referenced here.
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Affiliation(s)
- Narasimharao Nalabothula
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland, Baltimore, School of Medicine, Department of Radiation Oncology, Baltimore, Maryland
| | - Fred E. Indig
- National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - France Carrier
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland, Baltimore, School of Medicine, Department of Radiation Oncology, Baltimore, Maryland
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Bui QT, Golinelli-Cohen MP, Jackson CL. Large Arf1 guanine nucleotide exchange factors: evolution, domain structure, and roles in membrane trafficking and human disease. Mol Genet Genomics 2009; 282:329-50. [PMID: 19669794 PMCID: PMC7088145 DOI: 10.1007/s00438-009-0473-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 07/19/2009] [Indexed: 12/16/2022]
Abstract
The Sec7 domain ADP-ribosylation factor (Arf) guanine nucleotide exchange factors (GEFs) are found in all eukaryotes, and are involved in membrane remodeling processes throughout the cell. This review is focused on members of the GBF/Gea and BIG/Sec7 subfamilies of Arf GEFs, all of which use the class I Arf proteins (Arf1-3) as substrates, and play a fundamental role in trafficking in the endoplasmic reticulum (ER)—Golgi and endosomal membrane systems. Members of the GBF/Gea and BIG/Sec7 subfamilies are large proteins on the order of 200 kDa, and they possess multiple homology domains. Phylogenetic analyses indicate that both of these subfamilies of Arf GEFs have members in at least five out of the six eukaryotic supergroups, and hence were likely present very early in eukaryotic evolution. The homology domains of the large Arf1 GEFs play important functional roles, and are involved in interactions with numerous protein partners. The large Arf1 GEFs have been implicated in several human diseases. They are crucial host factors for the replication of several viral pathogens, including poliovirus, coxsackievirus, mouse hepatitis coronavirus, and hepatitis C virus. Mutations in the BIG2 Arf1 GEF have been linked to autosomal recessive periventricular heterotopia, a disorder of neuronal migration that leads to severe malformation of the cerebral cortex. Understanding the roles of the Arf1 GEFs in membrane dynamics is crucial to a full understanding of trafficking in the secretory and endosomal pathways, which in turn will provide essential insights into human diseases that arise from misregulation of these pathways.
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Affiliation(s)
- Quynh Trang Bui
- Laboratoire d'Enzymologie et Biochimie Structurales, Bat 34, CNRS, 1, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
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Interaction of brefeldin A-inhibited guanine nucleotide-exchange protein (BIG) 1 and kinesin motor protein KIF21A. Proc Natl Acad Sci U S A 2008; 105:18788-93. [PMID: 19020088 DOI: 10.1073/pnas.0810104105] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Brefeldin A-inhibited guanine nucleotide-exchange protein (BIG) 1 activates human ADP-ribosylation factor (ARF) 1 and 3 by accelerating the replacement of ARF-bound GDP with GTP to initiate recruitment of coat proteins for membrane vesicle formation. Liquid chromatography MS/MS analysis of peptides from proteins that co-precipitated with BIG1 antibodies identified "kinesin family member 21A" (KIF21A), a plus-end-directed motor protein that moves cargo on microtubules away from the microtubule-organizing center. Reciprocal immunoprecipitation (IP) of endogenous proteins and microscopically apparent overlap of immunoreactive BIG1 with overexpressed GFP-KIF21A in the perinuclear region were consistent with an interaction of KIF21A-BIG1. Overexpression of full-length KIF21A and BIG1 and their fragments in HEK293 cells followed by reciprocal IP revealed that the C-terminal tail of KIF21A, with seven WD-40 repeats, may interact with structure in the C-terminal region of BIG1. Interfering with cyclic activation and inactivation of ARF1 by overexpressing constitutively active ARF1(Q71L) or dominant inactive ARF1(T31N) altered the distribution of BIG1 as well as its interaction with KIF21A. A requirement for ARF1 was confirmed by its selective depletion with siRNA. Unlike disruption of microtubules with nocodazole, selective inhibition of transport by depletion of KIF21A with specific siRNA altered BIG1 distribution without changing that of intrinsic Golgi membrane proteins. These newly recognized interactions of BIG1 and KIF21A should enable us to understand better the mechanisms through which, acting together, they may integrate local events in membrane trafficking with longer-range transport processes and to relate those processes to the diverse signaling and scaffold functions of BIG1.
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