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Shahid M, Azfaralariff A, Zubair M, Abdulkareem Najm A, Khalili N, Law D, Firasat S, Fazry S. In silico study of missense variants of FANCA, FANCC and FANCG genes reveals high risk deleterious alleles predisposing to Fanconi anemia pathogenesis. Gene 2021; 812:146104. [PMID: 34864095 DOI: 10.1016/j.gene.2021.146104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/05/2021] [Accepted: 11/16/2021] [Indexed: 11/04/2022]
Abstract
Among the 22 Fanconi anemia (FA) reported genes, 90% of mutational spectra were found in three genes, namely FANCA (64%), FANCC (12%) and FANCG (8%). Therefore, this study aimed to identify the high-risk deleterious variants in three selected genes (FANCA, FANCC, and FANCG) through various computational approaches. The missense variant datasets retrieved from the UCSC genome browser were analyzed for their pathogenicity, stability, and phylogenetic conservancy. A total of 23 alterations, of which 16 in FANCA, 6 in FANCC and one variant in FANCG, were found to be highly deleterious. The native and mutant structures were generated, which demonstrated a profound impact on the respective proteins. Besides, their pathway analysis predicted many other pathways in addition to the Fanconi anemia pathway, homologous recombination, and mismatch repair pathways. Hence, this is the first comprehensive study that can be useful for understanding the genetic signatures in the development of FA.
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Affiliation(s)
- Muhammad Shahid
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Ahmad Azfaralariff
- Department of Food Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Muhammad Zubair
- Department of Wildlife and Ecology, University of Veterinary and Animal Sciences, Pattoki Campus, Pakistan
| | - Ahmed Abdulkareem Najm
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Nahid Khalili
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Douglas Law
- Faculty of Health and Life Sciences, Inti International University, Persiaran Perdana BBN Putra Nilai, 71800 Nilai, Negeri Sembilan
| | - Sabika Firasat
- Department of Zoology, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, 45320 Islamabad, Pakistan
| | - Shazrul Fazry
- Department of Food Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia; ZACH Biotech Depot Private Limited, Cheras, 43300, Selangor, Malaysia; Tasik Chini Research Center, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
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Nuclear accumulation of SHIP1 mutants derived from AML patients leads to increased proliferation of leukemic cells. Cell Signal 2018; 49:87-94. [PMID: 29852247 DOI: 10.1016/j.cellsig.2018.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/18/2018] [Accepted: 05/18/2018] [Indexed: 11/22/2022]
Abstract
The inositol 5-phosphatase SHIP1 acts as negative regulator of intracellular signaling in myeloid cells and is a tumor suppressor in myeloid leukemogenesis. After relocalization from the cytoplasm to the plasma membrane SHIP1 terminates PI3-kinase mediated signaling processes. Furthermore, SHIP1 is also found in distinct puncta in the cell nucleus and nuclear SHIP1 has a pro-proliferative function. Here we report the identification of five nuclear export signals (NESs) which regulate together with the two known nuclear localization signals (NLSs) the nucleocytoplasmic shuttling of SHIP1. Mutation of NLSs reduced the nuclear import and mutation of NESs decreased the nuclear export of SHIP1 in the acute myeloid leukemia (AML) cell line UKE-1. Interestingly, four SHIP1 mutants (K210R, N508D, V684E, Q1153L) derived from AML patients showed a nuclear accumulation after expression in UKE-1 cells. In addition, overexpression of the AML patient-derived mutation N508D caused an increased proliferation rate of UKE-1 cells in comparison to wild type SHIP1. Furthermore, we identified serine and tyrosine phosphorylation as a molecular mechanism for the regulation of nucleocytoplasmic shuttling of SHIP1 where tyrosine phosphorylation of distinct residues i.e. Y864, Y914, Y1021 reduces nuclear localization, whereas serine phosphorylation at S933 enhances nuclear localization of SHIP1. In summary, our data further implicate nuclear SHIP1 in cellular signaling and suggest that enhanced accumulation of SHIP1 mutants in the nucleus may be a contributory factor of abnormally high proliferation of AML cells.
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A germline FANCA alteration that is associated with increased sensitivity to DNA damaging agents. Cold Spring Harb Mol Case Stud 2017; 3:mcs.a001487. [PMID: 28864460 PMCID: PMC5593159 DOI: 10.1101/mcs.a001487] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 04/27/2017] [Indexed: 12/26/2022] Open
Abstract
Defects in genes involved in DNA damage repair (DDR) pathway are emerging as novel biomarkers and targets for new prostate cancer drug therapies. A previous report revealed an association between an exceptional response to cisplatin treatment and a somatic loss of heterozygosity (LOH) of FANCA in a patient with metastatic prostate cancer who also harbored a germline FANCA variant (S1088F). Although germline FANCA mutations are the most frequent alterations in patients with Fanconi anemia, germline alterations are less common in prostate cancer. We hypothesized that the germline S1088F FANCA variant in combination with FANCA LOH was deleterious for FANCA function and contributed to the patient's exceptional response to cisplatin. We show that although it properly localizes to the nucleus, the S1088F FANCA mutant protein disrupts the FANC protein complex resulting in increased sensitivity to DNA damaging agents. Because molecular stratification is emerging as a strategy for treating men with metastatic, castrate-resistant prostate cancer harboring specific DDR gene defects, our findings suggest that more biomarker studies are needed to better define clinically relevant germline and somatic alterations.
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Palovcak A, Liu W, Yuan F, Zhang Y. Maintenance of genome stability by Fanconi anemia proteins. Cell Biosci 2017; 7:8. [PMID: 28239445 PMCID: PMC5320776 DOI: 10.1186/s13578-016-0134-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/07/2016] [Indexed: 12/20/2022] Open
Abstract
Persistent dysregulation of the DNA damage response and repair in cells causes genomic instability. The resulting genetic changes permit alterations in growth and proliferation observed in virtually all cancers. However, an unstable genome can serve as a double-edged sword by providing survival advantages in the ability to evade checkpoint signaling, but also creating vulnerabilities through dependency on alternative genomic maintenance factors. The Fanconi anemia pathway comprises an intricate network of DNA damage signaling and repair that are critical for protection against genomic instability. The importance of this pathway is underlined by the severity of the cancer predisposing syndrome Fanconi anemia which can be caused by biallelic mutations in any one of the 21 genes known thus far. This review delineates the roles of the Fanconi anemia pathway and the molecular actions of Fanconi anemia proteins in confronting replicative, oxidative, and mitotic stress.
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Affiliation(s)
- Anna Palovcak
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
| | - Wenjun Liu
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
| | - Fenghua Yuan
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
| | - Yanbin Zhang
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
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Nuclear Export Signal Masking Regulates HIV-1 Rev Trafficking and Viral RNA Nuclear Export. J Virol 2017; 91:JVI.02107-16. [PMID: 27852860 DOI: 10.1128/jvi.02107-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 11/14/2016] [Indexed: 12/28/2022] Open
Abstract
HIV-1's Rev protein forms a homo-oligomeric adaptor complex linking viral RNAs to the cellular CRM1/Ran-GTP nuclear export machinery through the activity of Rev's prototypical leucine-rich nuclear export signal (NES). In this study, we used a functional fluorescently tagged Rev fusion protein as a platform to study the effects of modulating Rev NES identity, number, position, or strength on Rev subcellular trafficking, viral RNA nuclear export, and infectious virion production. We found that Rev activity was remarkably tolerant of diverse NES sequences, including supraphysiological NES (SNES) peptides that otherwise arrest CRM1 transport complexes at nuclear pores. Rev's ability to tolerate a SNES was both position and multimerization dependent, an observation consistent with a model wherein Rev self-association acts to transiently mask the NES peptide(s), thereby biasing Rev's trafficking into the nucleus. Combined imaging and functional assays also indicated that NES masking underpins Rev's well-known tendency to accumulate at the nucleolus, as well as Rev's capacity to activate optimal levels of late viral gene expression. We propose that Rev multimerization and NES masking regulates Rev's trafficking to and retention within the nucleus even prior to RNA binding. IMPORTANCE HIV-1 infects more than 34 million people worldwide causing >1 million deaths per year. Infectious virion production is activated by the essential viral Rev protein that mediates nuclear export of intron-bearing late-stage viral mRNAs. Rev's shuttling into and out of the nucleus is regulated by the antagonistic activities of both a peptide-encoded N-terminal nuclear localization signal and C-terminal nuclear export signal (NES). How Rev and related viral proteins balance strong import and export activities in order to achieve optimal levels of viral gene expression is incompletely understood. We provide evidence that multimerization provides a mechanism by which Rev transiently masks its NES peptide, thereby biasing its trafficking to and retention within the nucleus. Targeted pharmacological disruption of Rev-Rev interactions should perturb multiple Rev activities, both Rev-RNA binding and Rev's trafficking to the nucleus in the first place.
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Solomon PJ, Margaret P, Rajendran R, Ramalingam R, Menezes GA, Shirley AS, Lee SJ, Seong MW, Park SS, Seol D, Seo SH. A case report and literature review of Fanconi Anemia (FA) diagnosed by genetic testing. Ital J Pediatr 2015; 41:38. [PMID: 25953249 PMCID: PMC4438458 DOI: 10.1186/s13052-015-0142-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/22/2015] [Indexed: 12/29/2022] Open
Abstract
Fanconi anemia (FA) is a genetically heterogeneous rare autosomal recessive disorder characterized by congenital malformations, hematological problems and predisposition to malignancies. The genes that have been found to be mutated in FA patients are called FANC. To date 16 distinct FANC genes have been reported. Among these, mutations in FANCA are the most frequent among FA patients worldwide which account for 60- 65%. In this study, a nine years old male child was brought to our hospital one year ago for opinion and advice. He was the third child born to consanguineous parents. The mutation analyses were performed for proband, parents, elder sibling and the relatives [maternal aunt and maternal aunt’s son (cousin)]. Molecular genetic testing [targeted next-generation sequencing (MiSeq, Illumina method)] was performed by mutation analysis in 15 genes involved. Entire coding exons and their flanking regions of the genes were analysed. Sanger sequencing [(ABI 3730 analyzer by Applied Biosystems)] was performed using primers specific for 43 coding exons of the FANCA gene. A novel splice site mutation, c.3066 + 1G > T, (IVS31 + 1G > T), homozygote was detected by sequencing in the patient. The above sequence variant was identified in heterozygous state in his parents. Further, the above sequence variant was not identified in other family members (elder sibling, maternal aunt and cousin). It is concluded that genetic study should be done if possible in all the cases of suspected FA, including siblings, parents and close blood relatives. It will help us to plan appropriate treatment and also to select suitable donor for hematopoietic stem cell transplantation and to plan for genetic counseling. In addition to the case report, the main focus of this manuscript was to review literature on role of FANCA gene in FA since large number of FANCA mutations and polymorphisms have been identified.
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Affiliation(s)
- Ponnumony John Solomon
- Department of Paediatrics, Sree Balaji Medical College and Hospital, Chennai, 600 044, India.
| | - Priya Margaret
- Department of Paediatrics, Sree Balaji Medical College and Hospital, Chennai, 600 044, India.
| | - Ramya Rajendran
- Department of Paediatrics, Sree Balaji Medical College and Hospital, Chennai, 600 044, India.
| | - Revathy Ramalingam
- Department of Physiology/Central research laboratory (CRL), Sree Balaji Medical College and Hospital, Chennai, 600 044, India.
| | - Godfred A Menezes
- College of Applied Medical Sciences and Molecular Diagnostics and Personalised Therapeutics Unit (MDPTU), Ha'il University, Ha'il, Kingdom of Saudi Arabia (KSA). .,Worked previously as in-charge and scientist in Central Research Laboratory (CRL), Sree Balaji Medical College and Hospital, Chennai, 600 044, India.
| | - Alph S Shirley
- Department of Paediatrics, Sree Balaji Medical College and Hospital, Chennai, 600 044, India.
| | - Seung Jun Lee
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
| | - Moon-Woo Seong
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
| | - Sung Sup Park
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
| | - Dodam Seol
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
| | - Soo Hyun Seo
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul, Korea.
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Kim S, Hwang SK, Lee M, Kwak H, Son K, Yang J, Kim SH, Lee CH. Fanconi anemia complementation group A (FANCA) localizes to centrosomes and functions in the maintenance of centrosome integrity. Int J Biochem Cell Biol 2013; 45:1953-61. [PMID: 23806870 DOI: 10.1016/j.biocel.2013.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 06/07/2013] [Accepted: 06/16/2013] [Indexed: 02/07/2023]
Abstract
Fanconi anemia (FA) proteins are known to play roles in the cellular response to DNA interstrand cross-linking lesions; however, several reports have suggested that FA proteins play additional roles. To elucidate novel functions of FA proteins, we used yeast two-hybrid screening to identify binding partners of the Fanconi anemia complementation group A (FANCA) protein. The candidate proteins included never-in-mitosis-gene A (NIMA)-related kinase 2 (Nek2), which functions in the maintenance of centrosome integrity. The interaction of FANCA and Nek2 was confirmed in human embryonic kidney (HEK) 293T cells. Furthermore, FANCA interacted with γ-tubulin and localized to centrosomes, most notably during the mitotic phase, confirming that FANCA is a centrosomal protein. Knockdown of FANCA increased the frequency of centrosomal abnormalities and enhanced the sensitivity of U2OS osteosarcoma cells to nocodazole, a microtubule-interfering agent. In vitro kinase assays indicated that Nek2 can phosphorylate FANCA at threonine-351 (T351), and analysis with a phospho-specific antibody confirmed that this phosphorylation occurred in response to nocodazole treatment. Furthermore, U2OS cells overexpressing the phosphorylation-defective T351A FANCA mutant showed numerical centrosomal abnormalities, aberrant mitotic arrest, and enhanced nocodazole sensitivity, implying that the Nek2-mediated T351 phosphorylation of FANCA is important for the maintenance of centrosomal integrity. Taken together, this study revealed that FANCA localizes to centrosomes and is required for the maintenance of centrosome integrity, possibly through its phosphorylation at T351 by Nek2.
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Affiliation(s)
- Sunshin Kim
- New Experimental Therapeutics Branch, Research Institute, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang, Gyeonggi 410-769, Republic of Korea
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Litim N, Labrie Y, Desjardins S, Ouellette G, Plourde K, Belleau P, Durocher F. Polymorphic variations in the FANCA gene in high-risk non-BRCA1/2 breast cancer individuals from the French Canadian population. Mol Oncol 2012; 7:85-100. [PMID: 23021409 DOI: 10.1016/j.molonc.2012.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 08/17/2012] [Accepted: 08/21/2012] [Indexed: 12/25/2022] Open
Abstract
The majority of genes associated with breast cancer susceptibility, including BRCA1 and BRCA2 genes, are involved in DNA repair mechanisms. Moreover, among the genes recently associated with an increased susceptibility to breast cancer, four are Fanconi Anemia (FA) genes: FANCD1/BRCA2, FANCJ/BACH1/BRIP1, FANCN/PALB2 and FANCO/RAD51C. FANCA is implicated in DNA repair and has been shown to interact directly with BRCA1. It has been proposed that the formation of FANCA/G (dependent upon the phosphorylation of FANCA) and FANCB/L sub-complexes altogether with FANCM, represent the initial step for DNA repair activation and subsequent formation of other sub-complexes leading to ubiquitination of FANCD2 and FANCI. As only approximately 25% of inherited breast cancers are attributable to BRCA1/2 mutations, FANCA therefore becomes an attractive candidate for breast cancer susceptibility. We thus analyzed FANCA gene in 97 high-risk French Canadian non-BRCA1/2 breast cancer individuals by direct sequencing as well as in 95 healthy control individuals from the same population. Among a total of 85 sequence variants found in either or both series, 28 are coding variants and 19 of them are missense variations leading to amino acid change. Three of the amino acid changes, namely Thr561Met, Cys625Ser and particularly Ser1088Phe, which has been previously reported to be associated with FA, are predicted to be damaging by the SIFT and PolyPhen softwares. cDNA amplification revealed significant expression of 4 alternative splicing events (insertion of an intronic portion of intron 10, and the skipping of exons 11, 30 and 31). In silico analyzes of relevant genomic variants have been performed in order to identify potential variations involved in the expression of these spliced transcripts. Sequence variants in FANCA could therefore be potential spoilers of the Fanconi-BRCA pathway and as a result, they could in turn have an impact in non-BRCA1/2 breast cancer families.
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Affiliation(s)
- Nadhir Litim
- Cancer Genomics Laboratory, Division of Endocrinology and Genomics of CHUQ Research Centre and Laval University, Québec G1V 4G2, Canada
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Nuclear import and export signals of human cohesins SA1/STAG1 and SA2/STAG2 expressed in Saccharomyces cerevisiae. PLoS One 2012; 7:e38740. [PMID: 22715410 PMCID: PMC3371031 DOI: 10.1371/journal.pone.0038740] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 05/09/2012] [Indexed: 02/02/2023] Open
Abstract
Background Human SA/STAG proteins, homologues of the yeast Irr1/Scc3 cohesin, are the least studied constituents of the sister chromatid cohesion complex crucial for proper chromosome segregation. The two SA paralogues, SA1 and SA2, show some specificity towards the chromosome region they stabilize, and SA2, but not SA1, has been shown to participate in transcriptional regulation as well. The molecular basis of this functional divergence is unknown. Methodology/Principal Findings In silico analysis indicates numerous putative nuclear localization (NLS) and export (NES) signals in the SA proteins, suggesting the possibility of their nucleocytoplasmic shuttling. We studied the functionality of those putative signals by expressing fluorescently tagged SA1 and SA2 in the yeast Saccharomyces cerevisiae. Only the N-terminal NLS turned out to be functional in SA1. In contrast, the SA2 protein has at least two functional NLS and also two functional NES. Depending on the balance between these opposing signals, SA2 resides in the nucleus or is distributed throughout the cell. Validation of the above conclusions in HeLa cells confirmed that the same N-terminal NLS of SA1 is functional in those cells. In contrast, in SA2 the principal NLS functioning in HeLa cells is different from that identified in yeast and is localized to the C-terminus. Conclusions/Significance This is the first demonstration of the possibility of non-nuclear localization of an SA protein. The reported difference in the organization between the two SA homologues may also be relevant to their partially divergent functions. The mechanisms determining subcellular localization of cohesins are only partially conserved between yeast and human cells.
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Fanconi anemia proteins and their interacting partners: a molecular puzzle. Anemia 2012; 2012:425814. [PMID: 22737580 PMCID: PMC3378961 DOI: 10.1155/2012/425814] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 03/13/2012] [Indexed: 11/17/2022] Open
Abstract
In recent years, Fanconi anemia (FA) has been the subject of intense investigations, primarily in the DNA repair research field. Many discoveries have led to the notion of a canonical pathway, termed the FA pathway, where all FA proteins function sequentially in different protein complexes to repair DNA cross-link damages. Although a detailed architecture of this DNA cross-link repair pathway is emerging, the question of how a defective DNA cross-link repair process translates into the disease phenotype is unresolved. Other areas of research including oxidative metabolism, cell cycle progression, apoptosis, and transcriptional regulation have been studied in the context of FA, and some of these areas were investigated before the fervent enthusiasm in the DNA repair field. These other molecular mechanisms may also play an important role in the pathogenesis of this disease. In addition, several FA-interacting proteins have been identified with roles in these “other” nonrepair molecular functions. Thus, the goal of this paper is to revisit old ideas and to discuss protein-protein interactions related to other FA-related molecular functions to try to give the reader a wider perspective of the FA molecular puzzle.
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García-Santisteban I, Bañuelos S, Rodríguez JA. A global survey of CRM1-dependent nuclear export sequences in the human deubiquitinase family. Biochem J 2012; 441:209-17. [PMID: 21888622 DOI: 10.1042/bj20111300] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The mechanisms that regulate the nucleocytoplasmic localization of human deubiquitinases remain largely unknown. The nuclear export receptor CRM1 binds to specific amino acid motifs termed NESs (nuclear export sequences). By using in silico prediction and experimental validation of candidate sequences, we identified 32 active NESs and 78 inactive NES-like motifs in human deubiquitinases. These results allowed us to evaluate the performance of three programs widely used for NES prediction, and to add novel information to the recently redefined NES consensus. The novel NESs identified in the present study reveal a subset of 22 deubiquitinases bearing motifs that might mediate their binding to CRM1. We tested the effect of the CRM1 inhibitor LMB (leptomycin B) on the localization of YFP (yellow fluorescent protein)- or GFP (green fluorescent protein)-tagged versions of six NES-bearing deubiquitinases [USP (ubiquitin-specific peptidase) 1, USP3, USP7, USP21, CYLD (cylindromatosis) and OTUD7B (OTU-domain-containing 7B)]. YFP-USP21 and, to a lesser extent, GFP-OTUD7B relocated from the cytoplasm to the nucleus in the presence of LMB, revealing their nucleocytoplasmic shuttling capability. Two sequence motifs in USP21 had been identified during our survey as active NESs in the export assay. Using site-directed mutagenesis, we show that one of these motifs mediates USP21 nuclear export, whereas the second motif is not functional in the context of full-length USP21.
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Affiliation(s)
- Iraia García-Santisteban
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain
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Liu Q, Yu J, Zhuo X, Jiang Q, Zhang C. Pericentrin contains five NESs and an NLS essential for its nucleocytoplasmic trafficking during the cell cycle. Cell Res 2010; 20:948-62. [PMID: 20567258 DOI: 10.1038/cr.2010.89] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Pericentrin, a conserved centrosomal component, provides the structural scaffold to anchor numerous centrosomal proteins, and thus plays an essential role in the organization and function of the centrosome and the mitotic spindle. Although pericentrin was shown to localize in the cytoplasm and reported to be sensitive to leptomycin B (LMB), a specific inhibitor of Crm1, the regions within pericentrin that serve as signals for transporting in and out of the nucleus have not yet been identified. In this study, we identified five novel nuclear export signals (NESs) in pericentrin with diverse export activities. All of the five NESs could bind to Crm1 in a LMB-sensitive way when mediating the nuclear export of pericentrin. We also demonstrated that the region of amino acids 8-42 in pericentrin contains a tripartite nuclear localization signal (NLS) consisting of three clusters of basic amino acids. The NLS of pericentrin binds to importin beta directly or via the adaptor importin alpha to form the import complex, which could be disrupted by RanQ69L, a dominant-negative Ran GTPase possessing high affinity for importin beta. Furthermore, we found that mutation of the NESs in full-length pericentrin results in both nuclear and cytoplasmic localization, and mutation of the NLS abolishes the nuclear import of pericentrin. On the basis of these results, we suggest that the NESs and NLS of pericentrin are essential for its subcellular localization and nucleocytoplasmic trafficking during the cell cycle.
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Lahaye F, Lespinasse F, Staccini P, Palin L, Paquis-Flucklinger V, Santucci-Darmanin S. hMSH5 is a nucleocytoplasmic shuttling protein whose stability depends on its subcellular localization. Nucleic Acids Res 2010; 38:3655-71. [PMID: 20185565 PMCID: PMC2887964 DOI: 10.1093/nar/gkq098] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
MSH5 is a MutS-homologous protein required for meiotic DNA recombination. In addition, recent studies suggest that the human MSH5 protein (hMSH5) participates to mitotic recombination and to the cellular response to DNA damage and thus raise the possibility that a tight control of hMSH5 function(s) may be important for genomic stability. With the aim to characterize mechanisms potentially involved in the regulation of hMSH5 activity, we investigated its intracellular trafficking properties. We demonstrate that hMSH5 possesses a CRM1-dependent nuclear export signal (NES) and a nuclear localization signal that participates to its nuclear targeting. Localization analysis of various mutated forms of hMSH5 by confocal microscopy indicates that hMSH5 shuttles between the nucleus and the cytoplasm. We also provide evidence suggesting that hMSH5 stability depends on its subcellular compartmentalization, hMSH5 being much less stable in the nucleus than in the cytoplasm. Together, these data suggest that hMSH5 activity may be regulated by nucleocytoplasmic shuttling and nuclear proteasomal degradation, both of these mechanisms contributing to the control of nuclear hMSH5 content. Moreover, data herein also support that in tissues where both hMSH5 and hMSH4 proteins are expressed, hMSH5 might be retained in the nucleus through masking of its NES by binding of hMSH4.
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Affiliation(s)
- François Lahaye
- FRE 3086 Instabilité génétique: Maladies rares et cancers, Université de Nice Sophia-Antipolis, CNRS, Nice Cedex 2, France
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Kachnic LA, Li L, Fournier L, Willers H. Fanconi anemia pathway heterogeneity revealed by cisplatin and oxaliplatin treatments. Cancer Lett 2010; 292:73-9. [PMID: 20034732 DOI: 10.1016/j.canlet.2009.11.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 10/19/2009] [Accepted: 11/06/2009] [Indexed: 01/01/2023]
Abstract
Genetic or epigenetic inactivation of the pathway formed by the Fanconi Anemia (FA) proteins occurs in several cancer types, including head and neck squamous cell carcinomas (HNSCC), rendering the affected tumors potentially hypersensitive to DNA crosslinking agents. However, the cytotoxicity of other commonly used cancer therapeutics in cells with FA pathway defects remains to be defined. Here, we focused on the effects of cisplatin and oxaliplatin in a panel of HNSCC and fibroblast cell lines. We found that FANCC- and FANCD2-mutant cells were unexpectedly more sensitive to platinum drugs than FANCA-mutant cells, and mono-ubiquitination of FANCD2, which is mediated by the FANCA and FANCC containing FA core complex was not required for platinum resistance. Interestingly, platinum hypersensitivity could be dissociated from mitomycin C hypersensitivity suggesting different underlying mechanisms. FANCD2 or RAD51 subnuclear foci were not useful as biomarkers of platinum hypersensitivity of FANCC/FANCD2-mutant cells. Our data add to an emerging body of evidence indicating that the FA pathway is not linear and that several protein subcomplexes with different functions exist. It will be important to establish biomarkers that can predict the sensitivity of tumors with specific FA defects to chemotherapeutic agents.
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Affiliation(s)
- Lisa A Kachnic
- Laboratory of Cellular and Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital Cancer Center, Charlestown, MA 02129, USA.
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15
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Antony PMA, Mäntele S, Mollenkopf P, Boy J, Kehlenbach RH, Riess O, Schmidt T. Identification and functional dissection of localization signals within ataxin-3. Neurobiol Dis 2009; 36:280-92. [DOI: 10.1016/j.nbd.2009.07.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 07/22/2009] [Accepted: 07/27/2009] [Indexed: 10/20/2022] Open
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16
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Neveling K, Endt D, Hoehn H, Schindler D. Genotype-phenotype correlations in Fanconi anemia. Mutat Res 2009; 668:73-91. [PMID: 19464302 DOI: 10.1016/j.mrfmmm.2009.05.006] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 03/30/2009] [Accepted: 05/12/2009] [Indexed: 11/30/2022]
Abstract
Although still incomplete, we now have a remarkably detailed and nuanced picture of both phenotypic and genotypic components of the FA spectrum. Initially described as a combination of pancytopenia with a limited number of physical anomalies, it was later recognized that additional features were compatible with the FA phenotype, including a form without detectable malformations (Estren-Dameshek variant). The discovery of somatic mosaicism extended the boundaries of the FA phenotype to cases even without any overt hematological manifestations. This clinical heterogeneity was augmented by new conceptualizations. There was the realization of a constant risk for the development of myelodysplasia and certain malignancies, including acute myelogenous leukemia and squamous cell carcinoma, and there was the emergence of a distinctive cellular phenotype. A striking degree of genetic heterogeneity became apparent with the delineation of at least 12 complementation groups and the identification of their underlying genes. Although functional genetic insights have fostered the interpretation of many phenotypic features, surprisingly few stringent genotype-phenotype connections have emerged. In addition to myriad genetic alterations, less predictable influences are likely to modulate the FA phenotype, including modifier genes, environmental factors and chance effects. In reviewing the current status of genotype-phenotype correlations, we arrive at a unifying hypothesis to explain the remarkably wide range of FA phenotypes. Given the large body of evidence that genomic instability is a major underlying mechanism of accelerated ageing phenotypes, we propose that the numerous FA variants can be viewed as differential modulations and compression in time of intrinsic biological ageing.
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Affiliation(s)
- Kornelia Neveling
- Department of Human and Medical Genetics, University of Wurzburg, Biozentrum, Am Hubland, Wurzburg D-97074, Germany
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17
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Neyton S, Lespinasse F, Lahaye F, Staccini P, Paquis-Flucklinger V, Santucci-Darmanin S. CRM1-dependent nuclear export and dimerization with hMSH5 contribute to the regulation of hMSH4 subcellular localization. Exp Cell Res 2007; 313:3680-93. [PMID: 17869244 DOI: 10.1016/j.yexcr.2007.08.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 08/09/2007] [Accepted: 08/14/2007] [Indexed: 10/22/2022]
Abstract
MSH4 and MSH5 are members of the MutS homolog family, a conserved group of proteins involved in DNA mismatch correction and homologous recombination. Although several studies have provided compelling evidences suggesting that MSH4 and MSH5 could act together in early and late stages of meiotic recombination, their precise roles are poorly understood and recent findings suggest that the human MSH4 protein may also exert a cytoplasmic function. Here we show that MSH4 is present in the cytoplasm and the nucleus of both testicular cells and transfected somatic cells. Confocal studies on transfected cells provide the first evidence that the subcellular localization of MSH4 is regulated, at least in part, by an active nuclear export pathway dependent on the exportin CRM1. We used deletion mapping and mutagenesis to define two functional nuclear export sequences within the C-terminal part of hMSH4 that mediate nuclear export through the CRM1 pathway. Our results suggest that CRM1 is also involved in MSH5 nuclear export. In addition, we demonstrate that dimerization of MSH4 and MSH5 facilitates their nuclear localization suggesting that dimerization may regulate the intracellular trafficking of these proteins. Our findings suggest that nucleocytoplasmic traffic may constitute a regulatory mechanism for MSH4 and MSH5 functions.
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Affiliation(s)
- Sophie Neyton
- Equipe M3R, UMR 6543, Université de Nice Sophia-Antipolis, CNRS, Faculté de Médecine, Avenue de Valombrose 06107, Nice Cedex 2, France
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18
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Oda T, Hayano T, Miyaso H, Takahashi N, Yamashita T. Hsp90 regulates the Fanconi anemia DNA damage response pathway. Blood 2007; 109:5016-26. [PMID: 17327415 DOI: 10.1182/blood-2006-08-038638] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heat shock protein 90 (Hsp90) regulates diverse signaling pathways. Emerging evidence suggests that Hsp90 inhibitors, such as 17-allylamino-17-demethoxygeldanamycin (17-AAG), enhance DNA damage-induced cell death, suggesting that Hsp90 may regulate cellular responses to genotoxic stress. However, the underlying mechanisms are poorly understood. Here, we show that the Fanconi anemia (FA) pathway is involved in the Hsp90-mediated regulation of genotoxic stress response. In the FA pathway, assembly of 8 FA proteins including FANCA into a nuclear multiprotein complex, and the complex-dependent activation of FANCD2 are critical events for cellular tolerance against DNA cross-linkers. Hsp90 associates with FANCA, in vivo and in vitro, in a 17-AAG-sensitive manner. Disruption of the FANCA/Hsp90 association by cellular treatment with 17-AAG induces rapid proteasomal degradation and cytoplasmic relocalization of FANCA, leading to impaired activation of FANCD2. Furthermore, 17-AAG promotes DNA cross-linker-induced cytotoxicity, but this effect is much less pronounced in FA pathway-defective cells. Notably, 17-AAG enhances DNA cross-linker-induced chromosome aberrations. In conclusion, our results identify FANCA as a novel client of Hsp90, suggesting that Hsp90 promotes activation of the FA pathway through regulation of intracellular turnover and trafficking of FANCA, which is critical for cellular tolerance against genotoxic stress.
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Affiliation(s)
- Tsukasa Oda
- Laboratory of Molecular Genetics, Department of Molecular and Cellular Biology, Institute of Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan
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Macé G, Briot D, Guervilly JH, Rosselli F. L'anémie de Fanconi : aspects cellulaires et moléculaires. ACTA ACUST UNITED AC 2007; 55:19-28. [PMID: 16904272 DOI: 10.1016/j.patbio.2006.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 04/05/2006] [Indexed: 11/25/2022]
Abstract
Fanconi anemia (FA) is a recessive human cancer prone syndrome featuring bone marrow failure, developmental abnormalities and hypersensitivity to DNA crosslinking agents exposure. 11 among 12 FA gene have been isolated. The biochemical functions of the FANC proteins remain poorly understood. Anyhow, to cope with DNA crosslinks a cell needs a functional FANC pathway. Moreover, the FANC proteins appear to be involved in cell protection against oxidative damage and in the control of TNF-alpha activity. In this review, we describe the current understanding of the FANC pathway and we present how it may be integrated in the complex networks of proteins involved in maintaining the cellular homeostasis.
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Affiliation(s)
- G Macé
- Equipe Voie FANC/BRCA et Cancer FRE 2939 CNRS, Institut Gustave-Roussy, 39, rue Camille-Desmoulins, 94805 Villejuif, France
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Bedard JEJ, Purnell JD, Ware SM. Nuclear import and export signals are essential for proper cellular trafficking and function of ZIC3. Hum Mol Genet 2006; 16:187-98. [PMID: 17185387 DOI: 10.1093/hmg/ddl461] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Missense, frameshift and nonsense mutations in the zinc finger transcription factor ZIC3 cause heterotaxy as well as isolated congenital heart disease. Previously, we developed transactivation and subcellular localization assays to test the function of ZIC3 point mutations. Aberrant cytoplasmic localization suggested that the pathogenesis of ZIC3 mutations results, at least in part, from failure of appropriate cellular trafficking. To further investigate this hypothesis, the nucleocytoplasmic shuttling properties of ZIC3 have been examined. Subcellular localization assays designed to span the entire open-reading frame of wild-type and mutant ZIC3 proteins identified the presence of nucleocytoplasmic transport signals. ZIC3 domain mapping indicates that a relatively large region containing the zinc finger binding sites and a known GLI interacting domain is required for transport to the nucleus. Site-directed mutagenesis of critical residues within two putative nuclear localization signals (NLSs) leads to loss of nuclear localization. No further decrease was observed when both NLS sites were mutated, suggesting that mutation of either NLS site is sufficient for loss of importin-mediated nuclear localization. Additionally, we identify a cryptic CRM-1-dependent nuclear export signal (NES) within ZIC3, and identify a mutation within this region in a patient with heterotaxy. These results provide the first evidence that control of cellular trafficking of ZIC3 is critical for function and suggest a possible mechanism for transcriptional control during left-right patterning. Identification of mutations in mapped NLS or NES domains in heterotaxy patients demonstrates the functional importance of these domains in cardiac morphogenesis and allows for integration of structural analysis with developmental function.
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Affiliation(s)
- James E J Bedard
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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Larder R, Karali D, Nelson N, Brown P. Fanconi anemia A is a nucleocytoplasmic shuttling molecule required for gonadotropin-releasing hormone (GnRH) transduction of the GnRH receptor. Endocrinology 2006; 147:5676-89. [PMID: 16946016 PMCID: PMC1975762 DOI: 10.1210/en.2006-0383] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
GnRH binds its cognate G protein-coupled GnRH receptor (GnRHR) located on pituitary gonadotropes and drives expression of gonadotropin hormones. There are two gonadotropin hormones, comprised of a common alpha- and hormone-specific beta-subunit, which are required for gonadal function. Recently we identified that Fanconi anemia a (Fanca), a DNA damage repair gene, is differentially expressed within the LbetaT2 gonadotrope cell line in response to stimulation with GnRH. FANCA is mutated in more than 60% of cases of Fanconi anemia (FA), a rare genetically heterogeneous autosomal recessive disorder characterized by bone marrow failure, endocrine tissue cancer susceptibility, and infertility. Here we show that induction of FANCA protein is mediated by the GnRHR and that the protein constitutively adopts a nucleocytoplasmic intracellular distribution pattern. Using inhibitors to block nuclear import and export and a GnRHR antagonist, we demonstrated that GnRH induces nuclear accumulation of FANCA and green fluorescent protein (GFP)-FANCA before exporting back to the cytoplasm using the nuclear export receptor CRM1. Using FANCA point mutations that locate GFP-FANCA to the cytoplasm (H1110P) or functionally uncouple GFP-FANCA (Q1128E) from the wild-type nucleocytoplasmic distribution pattern, we demonstrated that wild-type FANCA was required for GnRH-induced activation of gonadotrope cell markers. Cotransfection of H1110P and Q1128E blocked GnRH activation of the alphaGsu and GnRHR but not the beta-subunit gene promoters. We conclude that nucleocytoplasmic shuttling of FANCA is required for GnRH transduction of the alphaGSU and GnRHR gene promoters and propose that FANCA functions as a GnRH-induced signal transducer.
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Affiliation(s)
- Rachel Larder
- Medical Research Council, Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4JT, Scotland, United Kingdom
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Medhurst AL, Laghmani EH, Steltenpool J, Ferrer M, Fontaine C, de Groot J, Rooimans MA, Scheper RJ, Meetei AR, Wang W, Joenje H, de Winter JP. Evidence for subcomplexes in the Fanconi anemia pathway. Blood 2006; 108:2072-80. [PMID: 16720839 PMCID: PMC1895538 DOI: 10.1182/blood-2005-11-008151] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fanconi anemia (FA) is a genomic instability disorder, clinically characterized by congenital abnormalities, progressive bone marrow failure, and predisposition to malignancy. Cells derived from patients with FA display a marked sensitivity to DNA cross-linking agents, such as mitomycin C (MMC). This observation has led to the hypothesis that the proteins defective in FA are involved in the sensing or repair of interstrand cross-link lesions of the DNA. A nuclear complex consisting of a majority of the FA proteins plays a crucial role in this process and is required for the monoubiquitination of a downstream target, FANCD2. Two new FA genes, FANCB and FANCL, have recently been identified, and their discovery has allowed a more detailed study into the molecular architecture of the FA pathway. We demonstrate a direct interaction between FANCB and FANCL and that a complex of these proteins binds FANCA. The interaction between FANCA and FANCL is dependent on FANCB, FANCG, and FANCM, but independent of FANCC, FANCE, and FANCF. These findings provide a framework for the protein interactions that occur "upstream" in the FA pathway and suggest that besides the FA core complex different subcomplexes exist that may have specific functions other than the monoubiquitination of FANCD2.
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Affiliation(s)
- Annette L Medhurst
- Department of Clinical Genetics and Human Genetics, Vrije Universiteit University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
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Léveillé F, Ferrer M, Medhurst AL, Laghmani EH, Rooimans MA, Bier P, Steltenpool J, Titus TA, Postlethwait JH, Hoatlin ME, Joenje H, de Winter JP. The nuclear accumulation of the Fanconi anemia protein FANCE depends on FANCC. DNA Repair (Amst) 2006; 5:556-65. [PMID: 16513431 DOI: 10.1016/j.dnarep.2006.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 01/10/2006] [Accepted: 01/13/2006] [Indexed: 01/18/2023]
Abstract
The Fanconi anemia (FA) protein FANCE is an essential component of the nuclear FA core complex, which is required for monoubiquitination of the downstream target FANCD2, an important step in the FA pathway of DNA cross-link repair. FANCE is predominantly localized in the nucleus and acts as a molecular bridge between the FA core complex and FANCD2, through direct binding of both FANCC and FANCD2. At present, it is poorly understood how the nuclear accumulation of FANCE is regulated and therefore we investigated the nuclear localization of this FA protein. We found that FANCE has a strong tendency to localize in the nucleus, since the addition of a nuclear export signal does not interfere with the nuclear localization of FANCE. We also demonstrate that the nuclear accumulation of FANCE does not rely solely on its nuclear localization signal motifs, but also on FANCC. The other FA proteins are not involved in the nuclear accumulation of FANCE, indicating a tight relationship between FANCC and FANCE, as suggested from their direct interaction. Finally, we show that the region of FANCE interacting with FANCC appears to be different from the region involved in binding FANCD2. This strengthens the idea that FANCE recruits FANCD2 to the core complex, without interfering with the binding of FANCC.
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Affiliation(s)
- France Léveillé
- Department of Clinical Genetics and Human Genetics, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
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Abstract
A rare genetic disease, Fanconi anemia (FA), now attracts broader attention from cancer biologists and basic researchers in the DNA repair and ubiquitin biology fields as well as from hematologists. FA is a chromosome instability syndrome characterized by childhood-onset aplastic anemia, cancer or leukemia susceptibility, and cellular hypersensitivity to DNA crosslinking agents. Identification of 11 genes for FA has led to progress in the molecular understanding of this disease. FA proteins, including a ubiquitin ligase (FANCL), a monoubiquitinated protein (FANCD2), a helicase (FANCJ/BACH1/BRIP1), and a breast/ovarian cancer susceptibility protein (FANCD1/BRCA2), appear to cooperate in a pathway leading to the recognition and repair of damaged DNA. Molecular interactions among FA proteins and responsible proteins for other chromosome instability syndromes (BLM, NBS1, MRE11, ATM, and ATR) have also been found. Furthermore, inactivation of FA genes has been observed in a wide variety of human cancers in the general population. These findings have broad implications for predicting the sensitivity and resistance of tumors to widely used anticancer DNA crosslinking agents (cisplatin, mitomycin C, and melphalan). Here, we summarize recent progress in the molecular biology of FA and discuss roles of the FA proteins in DNA repair and cancer biology.
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Affiliation(s)
- Toshiyasu Taniguchi
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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