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Trypanosoma cruzi TcSRPK, the first prot ... oan SR protein-specific kinases
Trypanosoma cruzi TcSRPK, the first protozoan member of the SRPK family, is biochemically and functionally conserved with metazoan SR protein-specific kinases.
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A novel SR protein-specific kinase (SRPK) from the SRPK family was identified for the first time in a protozoan organism. The primary structure of the protein, named TcSRPK, presents a significant degree of identity with other metazoan members of the family. In vitro phosphorylation experiments showed that TcSRPK has the same substrate specificity relative to other SRPKs. TcSRPK was able to generate a mAb104-recognized phosphoepitope, a SRPK landmark. Expression of TcSRPK in different Schizosaccharomyces pombe strains lead to conserved phenotypes, indicating that TcSRPK is a functional homologue of metazoan SRPKs. In functional alternative splicing assays in vivo in HeLa cells, TcSRPK enhanced SR protein-dependent inclusion of the EDI exon of the fibronectin minigene. When tested in vitro, it inhibited splicing either on nuclear extracts or on splicing-deficient S100 extracts complemented with ASF/SF2. This inhibition was similar to that observed with human SRPK1. This work constitutes the first report of a member of this family of proteins and the existence of an SR-network in a protozoan organism. The implications in the origins and control of splicing are discussed.
Portal D, Lobo GS, Kadener S, Prasad J, Espinosa JM, Pereira CA, Tang Z, Lin RJ, Manley JL, Kornblihtt AR, Flawiá MM, Torres HN
Molecular and biochemical parasitology
2003-03-01 00:00
127
1
9-21
Amino Acid Sequence,Animals,Antibodies, Monoclonal,Cloning, Molecular,Genes, Protozoan,Globins,Hela Cells,Humans,Molecular Sequence Data,Protein Structure, Tertiary,Protein-Serine-Threonine Kinases,Schizosaccharomyces,Sequence Alignment,Sequence Homology, Amino Acid,Species Specificity,Trypanosoma cruzi,Antibodies, Monoclonal,Globins,Protein-Serine-Threonine Kinases
Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones en Ingeniera Gentica y Biologa Molecular, Consejo Nacional de Investigaciones Cientficas y Tcnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
Mol. Biochem. Parasitol.
0166-6851
S0166685102002992
382
True
12615332
