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Vieira da Silva Torchelsen FK, Fernandes Pedrosa TC, Rodrigues MP, de Aguiar AR, de Oliveira FM, Amarante GW, Sales-Junior PA, Branquinho RT, Gomes da Silva SP, Talvani A, Fonseca Murta SM, Martins FT, Braun RL, Teixeira RR, Furtado Mosqueira VC, Lana MD. Novel diamides inspired by protein kinase inhibitors as anti- Trypanosoma cruzi agents: in vitro and in vivo evaluations. Future Med Chem 2023; 15:1469-1489. [PMID: 37650735 DOI: 10.4155/fmc-2023-0090] [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] [Indexed: 09/01/2023] Open
Abstract
Background: Chagas disease is a life-threatening illness caused by Trypanosoma cruzi. The involvement of serine-/arginine-rich protein kinase in the T. cruzi life cycle is significant. Aims: To synthesize, characterize and evaluate the trypanocidal activity of diamides inspired by kinase inhibitor, SRPIN340. Material & Methods: Synthesis using a three-step process and characterization by infrared, nuclear magnetic resonance and high-resolution mass spectrometry were conducted. The selectivity index was obtained by the ratio of CC50/IC50 in two in vitro models. The most active compound, 3j, was evaluated using in vitro cytokine assays and assessing in vivo trypanocidal activity. Results: 3j activity in the macrophage J774 lineage showed an anti-inflammatory profile, and mice showed significantly reduced parasitemia and morbidity at low compound dosages. Conclusion: Novel diamide is active against T. cruzi in vitro and in vivo.
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Affiliation(s)
| | - Tamiles Caroline Fernandes Pedrosa
- Programa de Pós-Graduação em Ciências Biológicas, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
| | | | - Alex Ramos de Aguiar
- Departamento de Química, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 30130-171, Brazil
| | | | - Giovanni Wilson Amarante
- Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, 36036-900, Brazil
| | | | - Renata Tupinambá Branquinho
- Programa de Pós-Graduação em Ciências Farmacêuticas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
| | - Sirlaine Pio Gomes da Silva
- Programa de pós-graduação em Saúde e Nutrição, Escola de Nutrição, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
| | - André Talvani
- Programa de Pós-Graduação em Ciências Biológicas, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
- Programa de pós-graduação em Saúde e Nutrição, Escola de Nutrição, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
| | | | - Felipe Terra Martins
- Departamento de Química, Universidade Federal de Goiás, Goiânia, Goiás, 74001-970, Brazil
| | - Rodrigo Ligabue Braun
- Departamento de Ciências Farmacêuticas, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Rio Grande do Sul, 90050-170, Brazil
| | - Róbson Ricardo Teixeira
- Departamento de Química, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 30130-171, Brazil
| | - Vanessa Carla Furtado Mosqueira
- Programa de Pós-Graduação em Ciências Farmacêuticas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
| | - Marta de Lana
- Programa de Pós-Graduação em Ciências Farmacêuticas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
- Programa de Pós-Graduação em Ciências Biológicas, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400-000, Brazil
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Pimentel DC, Leopoldo JR, Teixeira LF, Barros MVDA, de Souza APM, Onofre TS, de Carvalho RL, Machado SA, Messias IG, Pinto CCDS, Poleto MD, Diogo MA, Mariotini-Moura C, Bressan GC, Teixeira RR, Fietto JLR, Vasconcellos RDS. First evidence of a serine arginine protein kinase (SRPK) in leishmania braziliensis and its potential as therapeutic target. Acta Trop 2023; 238:106801. [PMID: 36563831 DOI: 10.1016/j.actatropica.2022.106801] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Leishmaniasis is a parasitic disease found in tropical and subtropical regions around the world, caused by parasites of the genus Leishmania. The disease is a public health concern and presents clinical manifestations that can cause death, disability, and mutilation. The parasite has promastigote (vector) and amastigote (vertebrate host) forms and kinase enzymes are involved in this differentiation process. In the present investigation, we show, for the first time, evidence of a serine/arginine protein kinase in Leshmania braziliensis (LbSRPK). Our results show that amastigotes express more LbSRPK than promastigotes. Analogues of SRPIN340 (a known inhibitor of SRPK) were evaluated for their leishmanicidal activity and two of them, namely SRVIC22 and SRVIC32 showed important leishmanicidal activity in vitro. SRVIC22 and SRVIC32 were able to reduce the infection rate in macrophages and the number of intracellular amastigotes by 55 and 60%, respectively. Bioinformatics analysis revealed the existence of two different amino acid residues in the active site of LbSRPK compared to their human homologue (Tyr/Leu-and Ser/Tyr), which could explain the absence of leishmanicidal activity of SRPIN340 on infected macrophages. In order to enhance leishmanicidal activity of the analogues, optimizations were proposed in the structures of the ligands, suggesting strong interactions with the catalytic site of LbSRPK. Although the evidence on the action of inhibitors upon LbSRPK is only indirect, our studies not only reveal, for the first time, evidence of a SRPK in Leishmania, but also shed light on a new therapeutic target for drug development.
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Affiliation(s)
- Débora Cristina Pimentel
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Juliana Rodrigues Leopoldo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Leilane Ferreira Teixeira
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Marcus Vinícius de Andrade Barros
- Departamento de Química, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Ana Paula Martins de Souza
- Departamento de Química, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Thiago Souza Onofre
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Rayane Luiza de Carvalho
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Sara Andrade Machado
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Isabelly Gonçalves Messias
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Carla Cristina de Souza Pinto
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Marcelo Depolo Poleto
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Marcel Arruda Diogo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Christiane Mariotini-Moura
- FAMINAS Muriaé, Bairro Universitário Muriaé, Av. Cristiano Ferreira Varella, 655, CEP, MG 36888-233, Brazil
| | - Gustavo Costa Bressan
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Robson Ricardo Teixeira
- Departamento de Química, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Juliana Lopes Rangel Fietto
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil
| | - Raphael de Souza Vasconcellos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP, Viçosa, MG 36570-900, Brazil.
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Rojas-Pirela M, Andrade-Alviárez D, Rojas V, Kemmerling U, Cáceres AJ, Michels PA, Concepción JL, Quiñones W. Phosphoglycerate kinase: structural aspects and functions, with special emphasis on the enzyme from Kinetoplastea. Open Biol 2020; 10:200302. [PMID: 33234025 PMCID: PMC7729029 DOI: 10.1098/rsob.200302] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Phosphoglycerate kinase (PGK) is a glycolytic enzyme that is well conserved among the three domains of life. PGK is usually a monomeric enzyme of about 45 kDa that catalyses one of the two ATP-producing reactions in the glycolytic pathway, through the conversion of 1,3-bisphosphoglycerate (1,3BPGA) to 3-phosphoglycerate (3PGA). It also participates in gluconeogenesis, catalysing the opposite reaction to produce 1,3BPGA and ADP. Like most other glycolytic enzymes, PGK has also been catalogued as a moonlighting protein, due to its involvement in different functions not associated with energy metabolism, which include pathogenesis, interaction with nucleic acids, tumorigenesis progression, cell death and viral replication. In this review, we have highlighted the overall aspects of this enzyme, such as its structure, reaction kinetics, activity regulation and possible moonlighting functions in different protistan organisms, especially both free-living and parasitic Kinetoplastea. Our analysis of the genomes of different kinetoplastids revealed the presence of open-reading frames (ORFs) for multiple PGK isoforms in several species. Some of these ORFs code for unusually large PGKs. The products appear to contain additional structural domains fused to the PGK domain. A striking aspect is that some of these PGK isoforms are predicted to be catalytically inactive enzymes or ‘dead’ enzymes. The roles of PGKs in kinetoplastid parasites are analysed, and the apparent significance of the PGK gene duplication that gave rise to the different isoforms and their expression in Trypanosoma cruzi is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaiso, Valparaiso 2373223, Chile
| | - Diego Andrade-Alviárez
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Verónica Rojas
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaiso, Valparaiso 2373223, Chile
| | - Ulrike Kemmerling
- Instituto de Ciencias Biomédicas, Universidad de Chile, Facultad de Medicina, Santiago de Chile 8380453, Santigo de Chile
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution, The King's Buildings, Edinburgh EH9 3FL, UK.,Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, UK
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
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Rojas-Pirela M, Rigden DJ, Michels PA, Cáceres AJ, Concepción JL, Quiñones W. Structure and function of Per-ARNT-Sim domains and their possible role in the life-cycle biology of Trypanosoma cruzi. Mol Biochem Parasitol 2017; 219:52-66. [PMID: 29133150 DOI: 10.1016/j.molbiopara.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/12/2017] [Accepted: 11/02/2017] [Indexed: 02/07/2023]
Abstract
Per-ARNT-Sim (PAS) domains of proteins play important roles as modules for signalling and cellular regulation processes in widely diverse organisms such as Archaea, Bacteria, protists, plants, yeasts, insects and vertebrates. These domains are present in many proteins where they are used as sensors of stimuli and modules for protein interactions. Characteristically, they can bind a broad spectrum of molecules. Such binding causes the domain to trigger a specific cellular response or to make the protein containing the domain susceptible to responding to additional physical or chemical signals. Different PAS proteins have the ability to sense redox potential, light, oxygen, energy levels, carboxylic acids, fatty acids and several other stimuli. Such proteins have been found to be involved in cellular processes such as development, virulence, sporulation, adaptation to hypoxia, circadian cycle, metabolism and gene regulation and expression. Our analysis of the genome of different kinetoplastid species revealed the presence of PAS domains also in different predicted kinases from these protists. Open-reading frames coding for these PAS-kinases are unusually large. In addition, the products of these genes appear to contain in their structure combinations of domains uncommon in other eukaryotes. The physiological significance of PAS domains in these parasites, specifically in Trypanosoma cruzi, is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, Scotland, United Kingdom
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela.
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Giannakouros T, Nikolakaki E, Mylonis I, Georgatsou E. Serine-arginine protein kinases: a small protein kinase family with a large cellular presence. FEBS J 2011; 278:570-86. [DOI: 10.1111/j.1742-4658.2010.07987.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Dixit A, Singh PK, Sharma GP, Malhotra P, Sharma P. PfSRPK1, a novel splicing-related kinase from Plasmodium falciparum. J Biol Chem 2010; 285:38315-23. [PMID: 20870716 DOI: 10.1074/jbc.m110.119255] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Even though it is increasingly evident that post-transcriptional events like mRNA processing and splicing may regulate gene expression and proteome diversity of malaria parasite Plasmodium, molecular mechanisms that regulate events like mRNA splicing in malaria parasite are poorly understood. Protein kinases control a wide variety of cellular events in almost all eukaryotes, including modulation of mRNA splicing, transport, and stability. We have identified a novel splicing-related protein kinase from Plasmodium falciparum, PfSRPK1. PfSRPK1 when incubated with parasite nuclear extracts inhibited RNA splicing, suggesting that it may control mRNA splicing in the parasite. PfSR1, a putative splicing factor from P. falciparum, was identified as a substrate of PfSRPK1. PfSR1 interacts with RNA and PfSRPK1 modulates its RNA binding. Early in the parasite development, PfSRPK1 and PfSR1 are present in the nucleus. These studies provide useful insights into the function of two potentially key components of P. falciparum mRNA splicing machinery.
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Affiliation(s)
- Aparna Dixit
- Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi 110067, India
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Liu S, Zhou Z, Lin Z, Ouyang Q, Zhang J, Tian S, Xing M. Identification of a nuclear localization motif in the serine/arginine protein kinase PSRPK of physarum polycephalum. BMC BIOCHEMISTRY 2009; 10:22. [PMID: 19703313 PMCID: PMC2754491 DOI: 10.1186/1471-2091-10-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Accepted: 08/25/2009] [Indexed: 11/13/2022]
Abstract
Background Serine/arginine (SR) protein-specific kinases (SRPKs) are conserved in a wide range of organisms, from humans to yeast. Studies showed that SRPKs can regulate the nuclear import of SR proteins in cytoplasm, and regulate the sub-localization of SR proteins in the nucleus. But no nuclear localization signal (NLS) of SRPKs was found. We isolated an SRPK-like protein PSRPK (GenBank accession No. DQ140379) from Physarum polycephalum previously, and identified a NLS of PSRPK in this study. Results We carried out a thorough molecular dissection of the different domains of the PSRPK protein involved in its nuclear localization. By truncation of PSRPK protein, deletion of and single amino acid substitution in a putative NLS and transfection of mammalian cells, we observed the distribution of PSRPK fluorescent fusion protein in mammalian cells using confocal microscopy and found that the protein was mainly accumulated in the nucleus; this indicated that the motif contained a nuclear localization signal (NLS). Further investigation with truncated PSPRK peptides showed that the NLS (318PKKGDKYDKTD328) was localized in the alkaline Ω-loop of a helix-loop-helix motif (HLHM) of the C-terminal conserved domain. If the 318PKKGDK322 sequence was deleted from the loop or K320 was mutated to T320, the PSRPK fluorescent fusion protein could not enter and accumulate in the nucleus. Conclusion This study demonstrated that the 318PKKGDKYDKTD328 peptides localized in the C-terminal conserved domain of PSRPK with the Ω-loop structure could play a crucial role in the NLS function of PSRPK.
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Affiliation(s)
- Shide Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering and College of Life Science, Shenzhen University, Shenzhen, PR China.
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Tsianou D, Nikolakaki E, Tzitzira A, Bonanou S, Giannakouros T, Georgatsou E. The enzymatic activity of SR protein kinases 1 and 1a is negatively affected by interaction with scaffold attachment factors B1 and 2. FEBS J 2009; 276:5212-27. [PMID: 19674106 DOI: 10.1111/j.1742-4658.2009.07217.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
SR protein kinases (SRPKs) phosphorylate Ser/Arg dipeptide-containing proteins that play crucial roles in a broad spectrum of basic cellular processes. Phosphorylation by SRPKs constitutes a major way of regulating such cellular mechanisms. In the past, we have shown that SRPK1a interacts with the nuclear matrix protein scaffold attachment factor B1 (SAFB1) via its unique N-terminal domain, which differentiates it from SRPK1. In this study, we show that SAFB1 inhibits the activity of both SRPK1a and SRPK1 in vitro and that its RE-rich region is redundant for the observed inhibition. We demonstrate that kinase activity inhibition is caused by direct binding of SAFB1 to SRPK1a and SRPK1, and we also present evidence for the in vitro binding of SAFB2 to the two kinases, albeit with different affinity. Moreover, we show that both SR protein kinases can form complexes with both scaffold attachment factors B in living cells and that this interaction is capable of inhibiting their activity, depending on the tenacity of the complex formed. Finally, we present data demonstrating that SRPK/SAFB complexes are present in the nucleus of HeLa cells and that the enzymatic activity of the nuclear matrixlocalized SRPK1 is repressed. These results suggest a new role for SAFB proteins as regulators of SRPK activity and underline the importance of the assembly of transient intranuclear complexes in cellular regulation.
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Affiliation(s)
- Dora Tsianou
- Department of Medicine, University of Thessaly, Mezourlo, 41110 Larissa, Greece
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Liu S, Kang K, Zhang J, Ouyang Q, Zhou Z, Tian S, Xing M. A novel Physarum polycephalum SR protein kinase specifically phosphorylates the RS domain of the human SR protein, ASF/SF2. Acta Biochim Biophys Sin (Shanghai) 2009; 41:657-67. [PMID: 19657567 DOI: 10.1093/abbs/gmp054] [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] [Indexed: 11/15/2022] Open
Abstract
A 1591-bp cDNA of a serine-rich protein kinase (SRPK)-like protein has been identified in Physarum polycephalum (GenBank accession No. DQ140379). The cDNA contains two repeat sequences at bp 1-153 and bp 395-547. The encoding sequence is 56% homologous to human SRPK1 and is named Physarum SRPK (PSRPK). Consistent with other SRPKs, the consensus motifs of PSRPK are within the two conserved domains (CDs). However, divergent motifs between the N-terminal and CDs are much shorter than the corresponding sequences of other SRPKs. To study the structure and function of this protein, we performed co-expression experiment in Escherichia coli and in vitro phosphorylation assay to investigate the phosphorylation effect of recombinant PSRPK on the human SR protein, ASF/SF2. Western blot analysis showed that PSRPK could phosphorylate ASF/SF2 in E. coli cells. Autoradiographic examination showed that both recombinant PSRPK and a truncated form of PSRPK with a 28-aa deletion at the N-terminus could phosphorylate ASF/SF2 and a truncated form of ASF/SF2 that contains the RS domain. However, these two forms of PSRPK could not phosphorylate a truncated form ASF/SF2 that lacks the RS domain. A truncated form of PSRPK that lacks either of CDs does not have any phosphorylation activity. These results indicated that, like other SRPKs, the phosphorylation site in PSRPK is located within the RS domain of the SR protein and that its phosphorylation activity is closely associated with the two CDs. This study on the structure and function of PSRPK demonstrates that it is a new member of the SRPK family.
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Affiliation(s)
- Shide Liu
- Shenzhen Key Laboratory of Microbial and Genetic Engineering, College of Life Science Shenzhen University, Shenzhen, China
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Hagiwara M. Alternative splicing: a new drug target of the post-genome era. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1754:324-31. [PMID: 16260193 DOI: 10.1016/j.bbapap.2005.09.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 09/07/2005] [Accepted: 09/10/2005] [Indexed: 11/18/2022]
Abstract
Alternative splicing allows for the creation of multiple distinct mRNA transcripts from a given gene in a multicellular organism. Pre-mRNA splicing is catalyzed by a multi-molecular complex, including serine/arginine-rich (SR) proteins, which are highly phosphorylated in living cells, and thought to play crucial roles in spliceosomal formation and in the regulation of alternative splicing. Recently, reports of low molecular compounds, which alter splicing pattern of genes, have been accumulated. A benzothiazole compound TG003, a kinase inhibitor that targets Clk1 and Clk4, suppressed dissociation of nuclear speckles, altered the splicing patterns, and rescued the embryonic defects induced by excessive Clk activity. The emerging inhibitors of the signal transduction pathways regulating pre-mRNA alternative splicing may open the way to therapies against diseases caused by missplicing.
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Affiliation(s)
- Masatoshi Hagiwara
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan.
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Parsons M, Worthey EA, Ward PN, Mottram JC. Comparative analysis of the kinomes of three pathogenic trypanosomatids: Leishmania major, Trypanosoma brucei and Trypanosoma cruzi. BMC Genomics 2005; 6:127. [PMID: 16164760 PMCID: PMC1266030 DOI: 10.1186/1471-2164-6-127] [Citation(s) in RCA: 273] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Accepted: 09/15/2005] [Indexed: 12/27/2022] Open
Abstract
Background The trypanosomatids Leishmania major, Trypanosoma brucei and Trypanosoma cruzi cause some of the most debilitating diseases of humankind: cutaneous leishmaniasis, African sleeping sickness, and Chagas disease. These protozoa possess complex life cycles that involve development in mammalian and insect hosts, and a tightly coordinated cell cycle ensures propagation of the highly polarized cells. However, the ways in which the parasites respond to their environment and coordinate intracellular processes are poorly understood. As a part of an effort to understand parasite signaling functions, we report the results of a genome-wide analysis of protein kinases (PKs) of these three trypanosomatids. Results Bioinformatic searches of the trypanosomatid genomes for eukaryotic PKs (ePKs) and atypical PKs (aPKs) revealed a total of 176 PKs in T. brucei, 190 in T. cruzi and 199 in L. major, most of which are orthologous across the three species. This is approximately 30% of the number in the human host and double that of the malaria parasite, Plasmodium falciparum. The representation of various groups of ePKs differs significantly as compared to humans: trypanosomatids lack receptor-linked tyrosine and tyrosine kinase-like kinases, although they do possess dual-specificity kinases. A relative expansion of the CMGC, STE and NEK groups has occurred. A large number of unique ePKs show no strong affinity to any known group. The trypanosomatids possess few ePKs with predicted transmembrane domains, suggesting that receptor ePKs are rare. Accessory Pfam domains, which are frequently present in human ePKs, are uncommon in trypanosomatid ePKs. Conclusion Trypanosomatids possess a large set of PKs, comprising approximately 2% of each genome, suggesting a key role for phosphorylation in parasite biology. Whilst it was possible to place most of the trypanosomatid ePKs into the seven established groups using bioinformatic analyses, it has not been possible to ascribe function based solely on sequence similarity. Hence the connection of stimuli to protein phosphorylation networks remains enigmatic. The presence of numerous PKs with significant sequence similarity to known drug targets, as well as a large number of unusual kinases that might represent novel targets, strongly argue for functional analysis of these molecules.
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Affiliation(s)
- Marilyn Parsons
- Seattle Biomedical Research Institute, 307 Westlake Ave. N., Seattle, WA, 98109 USA
- Department of Pathobiology, University of Washington, Seattle, WA, 98195 USA
| | - Elizabeth A Worthey
- Seattle Biomedical Research Institute, 307 Westlake Ave. N., Seattle, WA, 98109 USA
| | - Pauline N Ward
- Wellcome Centre for Molecular Parasitology, The Anderson College, University of Glasgow, Glasgow G11 6NU, UK
| | - Jeremy C Mottram
- Wellcome Centre for Molecular Parasitology, The Anderson College, University of Glasgow, Glasgow G11 6NU, UK
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Gubbels MJ, Wieffer M, Striepen B. Fluorescent protein tagging in Toxoplasma gondii: identification of a novel inner membrane complex component conserved among Apicomplexa. Mol Biochem Parasitol 2005; 137:99-110. [PMID: 15279956 DOI: 10.1016/j.molbiopara.2004.05.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Revised: 05/05/2004] [Accepted: 05/06/2004] [Indexed: 10/26/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite, and its sub-cellular organization shows clear adaptations to this life-style. In addition to organelles shared among all eukaryotes, the organism possesses a number of specialized compartments with important roles in host cell invasion and intra-cellular survival. These unique aspects of the parasite's biology are also reflected in its genome. The ongoing genome sequencing efforts for T. gondii and related apicomplexans predict a high proportion of genes unique to the phylum, which lack homologs in other model organisms. Knowing the sub-cellular localization of these gene products will be an important first step towards their functional characterization. We used a library approach wherein parasite genomic DNA was fused to the yellow fluorescent protein (YFP) gene. Parasites transformed with this library were screened by flow cytometry and fluorescence microscopy. Clones tagged in a wide variety of sub-cellular compartments (nucleus, mitochondria, ER, dense granules (secreted), spliceosome, plasma membrane, apicoplast, inner membrane complex) were isolated and confirmed using compartment specific markers. Clones with tags in parasite-specific localizations were subjected to insert rescue and phenotypic verification using an in vitro recombination system. Among the genes identified is a novel inner membrane complex gene (IMC3) conserved among Apicomplexa.
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Affiliation(s)
- Marc-Jan Gubbels
- Center for Tropical and Emerging Global Diseases, University of Georgia, 724 Biological Sciences Building, Athens 30602, USA
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