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Wang X, Hua X, Zhang H, Ren Y, Yang F, Zhu J. HABP4 overexpression promotes apoptosis in goat turbinate bone cells. Anim Biotechnol 2023; 34:4187-4195. [PMID: 35522841 DOI: 10.1080/10495398.2022.2062601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Hyaluronic acid-binding protein (HABP4) plays important roles in regulating cell cycle and apoptosis. However, its functions in regulating cell apoptosis remain unclear. To reveal the effects of HABP4 on cell proliferation, cell cycle and apoptosis, the HABP4 sequence was cloned, and we investigated the gain and loss functions of HABP4 in goat turbinate bone cells. Our results showed that a 1,496-bp HABP4 sequence was cloned successfully. The interference effect of siRNA1 on HABP4 was the strongest, reducing its mRNA expression level by 83%, decreasing the cells in the G0/G1 and S phases of the cell cycle and inhibiting cell growth and apoptosis. The overexpression of HABP4 produced contrasting results. Furthermore, an HABP4 knockdown caused the up-regulated expression of genes associated with apoptosis, including Bcl-2 and BCL2L11, but the down-regulation of Caspase3, Caspase7, Bax, PARP1, SOCS2 and P53 mRNA levels. Additionally, HABP4 overexpression significantly up-regulated the expression levels of Bax, Caspase3, Caspase7, BCL2L11, P53, SOCS2 and PARP1. However, the expression of Bcl-2 was down-regulated. These data provide an important foundation for further in-depth studies of HABP4 functions.
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Affiliation(s)
- Xianjun Wang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Xiang Hua
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Huanrong Zhang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Yupeng Ren
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Falong Yang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Jiangjiang Zhu
- Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization Key Laboratory of Sichuan Province, Chengdu, China
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2
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Colleti C, Melo-Hanchuk TD, da Silva FRM, Saito Â, Kobarg J. Complex interactomes and post-translational modifications of the regulatory proteins HABP4 and SERBP1 suggest pleiotropic cellular functions. World J Biol Chem 2019; 10:44-64. [PMID: 31768228 PMCID: PMC6872977 DOI: 10.4331/wjbc.v10.i3.44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/30/2019] [Accepted: 10/15/2019] [Indexed: 02/05/2023] Open
Abstract
The 57 kDa antigen recognized by the Ki-1 antibody, is also known as intracellular hyaluronic acid binding protein 4 and shares 40.7% identity and 67.4% similarity with serpin mRNA binding protein 1, which is also named CGI-55, or plasminogen activator inhibitor type-1-RNA binding protein-1, indicating that they might be paralog proteins, possibly with similar or redundant functions in human cells. Through the identification of their protein interactomes, both regulatory proteins have been functionally implicated in transcriptional regulation, mRNA metabolism, specifically RNA splicing, the regulation of mRNA stability, especially, in the context of the progesterone hormone response, and the DNA damage response. Both proteins also show a complex pattern of post-translational modifications, involving Ser/Thr phosphorylation, mainly through protein kinase C, arginine methylation and SUMOylation, suggesting that their functions and locations are highly regulated. Furthermore, they show a highly dynamic cellular localization pattern with localizations in both the cytoplasm and nucleus as well as punctuated localizations in both granular cytoplasmic protein bodies, upon stress, and nuclear splicing speckles. Several reports in the literature show altered expressions of both regulatory proteins in a series of cancers as well as mutations in their genes that may contribute to tumorigenesis. This review highlights important aspects of the structure, interactome, post-translational modifications, sub-cellular localization and function of both regulatory proteins and further discusses their possible functions and their potential as tumor markers in different cancer settings.
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Affiliation(s)
- Carolina Colleti
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-871, Brazil
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
| | - Talita Diniz Melo-Hanchuk
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
| | - Flávia Regina Moraes da Silva
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-871, Brazil
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
| | - Ângela Saito
- Laboratório Nacional de Biociências, CNPEM, Campinas 13083-970, Brazil
| | - Jörg Kobarg
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-871, Brazil
- Institute of Biology, Departament of Biochemistry and Tissue Biology, University of Campinas, Campinas 13083-862, Brazil
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3
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Saito Â, Souza EE, Costa FC, Meirelles GV, Gonçalves KA, Santos MT, Bressan GC, McComb ME, Costello CE, Whelan SA, Kobarg J. Human Regulatory Protein Ki-1/57 Is a Target of SUMOylation and Affects PML Nuclear Body Formation. J Proteome Res 2017; 16:3147-3157. [PMID: 28695742 DOI: 10.1021/acs.jproteome.7b00001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ki-1/57 is a nuclear and cytoplasmic regulatory protein first identified in malignant cells from Hodgkin's lymphoma. It is involved in gene expression regulation on both transcriptional and mRNA metabolism levels. Ki-1/57 belongs to the family of intrinsically unstructured proteins and undergoes phosphorylation by PKC and methylation by PRMT1. Previous characterization of its protein interaction profile by yeast two-hybrid screening showed that Ki-1/57 interacts with proteins of the SUMOylation machinery, the SUMO E2 conjugating enzyme UBC9 and the SUMO E3 ligase PIAS3, which suggested that Ki-1/57 could be involved with this process. Here we identified seven potential SUMO target sites (lysine residues) on Ki-1/57 sequence and observed that Ki-1/57 is modified by SUMO proteins in vitro and in vivo. We showed that SUMOylation of Ki-1/57 occurred on lysines 213, 276, and 336. In transfected cells expressing FLAG-Ki-1/57 wild-type, its paralog FLAG-CGI-55 wild-type, or their non-SUMOylated triple mutants, the number of PML-nuclear bodies (PML-NBs) is reduced compared with the control cells not expressing the constructs. More interestingly, after treating cells with arsenic trioxide (As2O3), the number of PML-NBs is no longer reduced when the non-SUMOylated triple mutant Ki-1/57 is expressed, suggesting that the SUMOylation of Ki-1/57 has a role in the control of As2O3-induced PML-NB formation. A proteome-wide analysis of Ki-1/57 partners in the presence of either SUMO-1 or SUMO-2 suggests that the involvement of Ki-1/57 with the regulation of gene expression is independent of the presence of either SUMO-1 or SUMO-2; however, the presence of SUMO-1 strongly influences the interaction of Ki-1/57 with proteins associated with cellular metabolism, maintenance, and cell cycle.
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Affiliation(s)
- Ângela Saito
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil
| | - Edmarcia E Souza
- Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas , Campinas, São Paulo 13083-859, Brazil
| | - Fernanda C Costa
- Instituto de Física de São Carlos, Universidade de São Paulo , São Carlos, São Paulo 13563-120, Brazil
| | - Gabriela V Meirelles
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil
| | - Kaliandra A Gonçalves
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) , Campinas, São Paulo 13083-970, Brazil
| | - Marcos T Santos
- ONKOS Molecular Diagnostics, Inc. , R&D Department, Ribeirão Preto, São Paulo 14056-680, Brazil
| | - Gustavo C Bressan
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa (UFV) , Viçosa, Minas Gerais 36570-000, Brazil
| | - Mark E McComb
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Catherine E Costello
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Stephen A Whelan
- Center for Biomedical Mass Spectrometry, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Jörg Kobarg
- Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas , Campinas, São Paulo 13083-859, Brazil.,Departamento de Bioquímica e Biologia Tecidual, Programa de Pós-graduação em Biologia Funcional e Molecular, Universidade Estadual de Campinas , Campinas, São Paulo 13083-862, Brazil
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4
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Dong C, Yang XZ, Zhang CY, Liu YY, Zhou RB, Cheng QD, Yan EK, Yin DC. Myocyte enhancer factor 2C and its directly-interacting proteins: A review. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 126:22-30. [DOI: 10.1016/j.pbiomolbio.2017.02.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 11/24/2016] [Accepted: 02/01/2017] [Indexed: 11/27/2022]
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5
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Costa FC, Saito A, Gonçalves KA, Vidigal PM, Meirelles GV, Bressan GC, Kobarg J. Ki-1/57 and CGI-55 ectopic expression impact cellular pathways involved in proliferation and stress response regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2944-56. [PMID: 25205453 DOI: 10.1016/j.bbamcr.2014.08.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/27/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
Abstract
Ki-1/57 (HABP4) and CGI-55 (SERBP1) are regulatory proteins and paralogs with 40.7% amino acid sequence identity and 67.4% similarity. Functionally, they have been implicated in the regulation of gene expression on both the transcriptional and mRNA metabolism levels. A link with tumorigenesis is suggested, since both paralogs show altered expression levels in tumor cells and the Ki-1/57 gene is found in a region of chromosome 9q that represents a haplotype for familiar colon cancer. However, the target genes regulated by Ki-1/57 and CGI-55 are unknown. Here, we analyzed the alterations of the global transcriptome profile after Ki-1/57 or CGI-55 overexpression in HEK293T cells by DNA microchip technology. We were able to identify 363 or 190 down-regulated and 50 or 27 up-regulated genes for Ki-1/57 and CGI-55, respectively, of which 20 were shared between both proteins. Expression levels of selected genes were confirmed by qRT-PCR both after protein overexpression and siRNA knockdown. The majority of the genes with altered expression were associated to proliferation, apoptosis and cell cycle control processes, prompting us to further explore these contexts experimentally. We observed that overexpression of Ki-1/57 or CGI-55 results in reduced cell proliferation, mainly due to a G1 phase arrest, whereas siRNA knockdown of CGI-55 caused an increase in proliferation. In the case of Ki-1/57 overexpression, we found protection from apoptosis after treatment with the ER-stress inducer thapsigargin. Together, our data give important new insights that may help to explain these proteins putative involvement in tumorigenic events.
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Affiliation(s)
- Fernanda C Costa
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil.
| | - Angela Saito
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Kaliandra A Gonçalves
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Pedro M Vidigal
- Laboratório de Bioinformática, Instituto de Biotecnologia Aplicada à Agropecuária-BIOAGRO, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil.
| | - Gabriela V Meirelles
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil.
| | - Gustavo C Bressan
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
| | - Jörg Kobarg
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brasil; Departamento de Bioquímica-Programa de Pós-graduação em Biologia Funcional e Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil; Departamento de Genética, Evolução e Bioagentes - Programa de Pós-graduação em Genética e Biologia Molecular, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brasil.
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6
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Gonçalves KDA, Bressan GC, Saito A, Morello LG, Zanchin NIT, Kobarg J. Evidence for the association of the human regulatory protein Ki-1/57 with the translational machinery. FEBS Lett 2011; 585:2556-60. [PMID: 21771594 DOI: 10.1016/j.febslet.2011.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Revised: 07/04/2011] [Accepted: 07/04/2011] [Indexed: 02/06/2023]
Abstract
Ki-1/57 is a cytoplasmic and nuclear protein of 57 kDa first identified in malignant cells from Hodgkin's lymphoma. Based on yeast-two hybrid protein interaction we found out that Ki-1/57 interacts with adaptor protein RACK1 (receptor of activated kinase 1), CIRP (cold-inducible RNA-binding protein), RPL38 (ribosomal protein L38) and FXR1 (fragile X mental retardation-related protein 1). Since these proteins are involved in the regulation of translation we suspected that Ki-1/57 may have a role in it. We show by immunoprecipitation the association of Ki-1/57 with FMRP. Confocal microscopy revealed that Ki-1/57 colocalizes with FMRP/FXR1/2 to stress granules. Furthermore Ki-1/57 cosediments with free ribosomal particles and enhances translation, when tethered to a reporter mRNA, suggesting that Ki-1/57 may be involved in translational regulation.
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Affiliation(s)
- Kaliandra de Almeida Gonçalves
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brazil
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7
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Identification and characterization of proteins that selectively interact with the LHR mRNA binding protein (LRBP) in rat ovaries. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:591-7. [PMID: 20167237 DOI: 10.1016/j.bbamcr.2010.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 01/21/2010] [Accepted: 02/08/2010] [Indexed: 01/21/2023]
Abstract
Luteinizing hormone receptor (LHR) mRNA binding protein (LRBP), identified as mevalonate kinase, has been shown to be a trans factor mediating the post-transcriptional regulation of LHR mRNA expression in ovaries. LRBP binds to the coding region of LHR mRNA and accelerates its degradation. Our previous studies in an in vitro system showed that LRBP represses the translation of LHR mRNA by forming an untranslatable ribonucleoprotein (mRNP) complex, further suggesting that the untranslatable mRNP complex is directed to the mRNA repression/decay machinery for subsequent mRNA turnover. In the present studies, we used yeast two-hybrid system to screen a cDNA library which was constructed from LHR down-regulated ovaries. Two proteins were identified interacting with LRBP: ribosomal protein S20 (RP S20) and ubiquitin conjugating enzyme 2i (UBCE2i). Their interactions with LRBP were confirmed by the mating assay, co-immunoprecipitation analyses and in vitro sumoylation assays. Furthermore, we show that LRBP is a target for modification by SUMO2/3 but not by SUMO1, at K256 and/or K345. Mutation of both lysine residues is sufficient to abrogate the sumoylation of LRBP. These findings suggest that the direct interaction of LRBP with the translation machinery, through RP S20, may be responsible for the transition of LHR mRNA to an untranslatable complex, and that sumoylation of LRBP may play a role in targeting the untranslatable mRNP complex to the mRNA decay machinery in specific cytoplasmic foci.
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8
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Bressan GC, Quaresma AJC, Moraes EC, Manfiolli AO, Passos DO, Gomes MD, Kobarg J. Functional association of human Ki-1/57 with pre-mRNA splicing events. FEBS J 2009; 276:3770-83. [PMID: 19523114 DOI: 10.1111/j.1742-4658.2009.07092.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The cytoplasmic and nuclear protein Ki-1/57 was first identified in malignant cells from Hodgkin's lymphoma. Despite studies showing its phosphorylation, arginine methylation, and interaction with several regulatory proteins, the functional role of Ki-1/57 in human cells remains to be determined. Here, we investigated the relationship of Ki-1/57 with RNA functions. Through immunoprecipitation assays, we verified the association of Ki-1/57 with the endogenous splicing proteins hnRNPQ and SFRS9 in HeLa cell extracts. We also found that recombinant Ki-1/57 was able to bind to a poly-U RNA probe in electrophoretic mobility shift assays. In a classic splicing test, we showed that Ki-1/57 can modify the splicing site selection of the adenoviral E1A minigene in a dose-dependent manner. Further confocal and fluorescence microscopy analysis revealed the localization of enhanced green fluorescent proteinKi-1/57 to nuclear bodies involved in RNA processing and or small nuclear ribonucleoprotein assembly, depending on the cellular methylation status and its N-terminal region. In summary, our findings suggest that Ki-1/57 is probably involved in cellular events related to RNA functions, such as pre-mRNA splicing.
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Angelelli C, Magli A, Ferrari D, Ganassi M, Matafora V, Parise F, Razzini G, Bachi A, Ferrari S, Molinari S. Differentiation-dependent lysine 4 acetylation enhances MEF2C binding to DNA in skeletal muscle cells. Nucleic Acids Res 2007; 36:915-28. [PMID: 18086704 PMCID: PMC2241889 DOI: 10.1093/nar/gkm1114] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Myocyte enhancer factor 2 (MEF2) proteins play a key role in promoting the expression of muscle-specific genes in differentiated muscle cells. MEF2 activity is regulated by the association with several transcriptional co-factors and by post-translational modifications. In the present report, we provide evidence for a novel regulatory mechanism of MEF2C activity, which occurs at the onset of skeletal muscle differentiation and is based on Lys4 acetylation. This covalent modification results in the enhancement of MEF2C binding to DNA and chromatin. In particular, we report that the kinetic parameters of MEF2/DNA association change substantially upon induction of differentiation to give a more stable complex and that this effect is mediated by Lys4 acetylation. We also show that Lys4 acetylation plays a prominent role in the p300-dependent activation of MEF2C.
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Affiliation(s)
- Cecilia Angelelli
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
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Nery FC, Bressan GC, Alborghetti MR, Passos DO, Kuniyoshi TM, Ramos CHI, Oyama S, Kobarg J. A spectroscopic analysis of the interaction between the human regulatory proteins RACK1 and Ki-1/57. Biol Chem 2006; 387:577-82. [PMID: 16740129 DOI: 10.1515/bc.2006.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ki-1/57 is a 57-kDa cytoplasmic and nuclear protein associated with protein kinase activity and is hyper-phosphorylated on Ser/Thr residues upon cellular activation. In previous studies we identified the receptor of activated kinase-1 (RACK1), a signaling adaptor protein that binds activated PKC, as a protein that interacts with Ki-1/57. Here we demonstrate that the far-UV circular dichroism spectrum of the WD repeat-containing RACK1 protein shows an unusual positive ellipticity at 229 nm, which in other proteins of the WD family has been attributed to surface tryptophans that are quenchable by N-bromosuccinimide (NBS). As well as NBS, in vitro binding of 6xHis-Ki-1/57(122-413) and 6xHis-Ki-1/57(264-413) can also quench the positive ellipticity of the RACK1 spectrum. We generated a model of RACK1 by homology modeling using a G protein beta subunit as template. Our model suggests the family-typical seven-bladed beta-propeller, with an aromatic cluster around the central tunnel that contains four Trp residues (17, 83, 150, 170), which are likely involved in the interaction with Ki-1/57.
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Affiliation(s)
- Flávia C Nery
- Centro de Biologia Molecular Estrutural, Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro 10.000, C.P. 6192, 13084-971 Campinas SP, Brazil
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11
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Passos DO, Bressan GC, Nery FC, Kobarg J. Ki-1/57 interacts with PRMT1 and is a substrate for arginine methylation. FEBS J 2006; 273:3946-61. [PMID: 16879614 DOI: 10.1111/j.1742-4658.2006.05399.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The human 57 kDa Ki-1 antigen (Ki-1/57) is a cytoplasmic and nuclear protein, associated with Ser/Thr protein kinase activity, and phosphorylated at the serine and threonine residues upon cellular activation. We have shown that Ki-1/57 interacts with chromo-helicase DNA-binding domain protein 3 and with the adaptor/signaling protein receptor of activated kinase 1 in the nucleus. Among the identified proteins that interacted with Ki-1/57 in a yeast two-hybrid system was the protein arginine-methyltransferase-1 (PRMT1). Most interestingly, when PRMT1 was used as bait in a yeast two-hybrid system we were able to identify Ki-1/57 as prey among 14 other interacting proteins, the majority of which are involved in RNA metabolism or in the regulation of transcription. We found that Ki-1/57 and its putative paralog CGI-55 have two conserved Gly/Arg-rich motif clusters (RGG/RXR box, where X is any amino acid) that may be substrates for arginine-methylation by PRMT1. We observed that all Ki-1/57 protein fragments containing RGG/RXR box clusters interact with PRMT1 and are targets for methylation in vitro. Furthermore, we found that Ki-1/57 is a target for methylation in vivo. Using immunofluorescence experiments we observed that treatment of HeLa cells with an inhibitor of methylation, adenosine-2',3'-dialdehyde (Adox), led to a reduction in the cytoplasmic immunostaining of Ki-1/57, whereas its paralog CGI-55 was partially redistributed from the nucleus to the cytoplasm upon Adox treatment. In summary, our data show that the yeast two-hybrid assay is an effective system for identifying novel PRMT arginine-methylation substrates and may be successfully applied to other members of the growing family of PRMTs.
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Affiliation(s)
- Dario O Passos
- Centro de Biologia Molecular Estrutural, Laboratório Nacional de Luz Síncrotron, Campinas, Brazil
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Nery FC, Rui E, Kuniyoshi TM, Kobarg J. Evidence for the interaction of the regulatory protein Ki-1/57 with p53 and its interacting proteins. Biochem Biophys Res Commun 2006; 341:847-55. [PMID: 16455055 DOI: 10.1016/j.bbrc.2006.01.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 01/11/2006] [Indexed: 12/15/2022]
Abstract
Ki-1/57 is a cytoplasmic and nuclear phospho-protein of 57 kDa and interacts with the adaptor protein RACK1, the transcription factor MEF2C, and the chromatin remodeling factor CHD3, suggesting that it might be involved in the regulation of transcription. Here, we describe yeast two-hybrid studies that identified a total of 11 proteins interacting with Ki-1/57, all of which interact or are functionally associated with p53 or other members of the p53 family of proteins. We further found that Ki-1/57 is able to interact with p53 itself in the yeast two-hybrid system when the interaction was tested directly. This interaction could be confirmed by pull down assays with purified proteins in vitro and by reciprocal co-immunoprecipitation assays from the human Hodgkin analogous lymphoma cell line L540. Furthermore, we found that the phosphorylation of p53 by PKC abolishes its interaction with Ki-1/57 in vitro.
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Affiliation(s)
- Flávia C Nery
- Centro de Biologia Molecular Estrutural, Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro 10.000, C.P. 6192, 13084-971 Campinas, SP, Brazil
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