RESUMO
Calcium-dependent protein kinases play a crucial role in intracellular calcium signaling in plants, some algae and protozoa. In Plasmodium falciparum, calcium-dependent protein kinase 1 (PfCDPK1) is expressed during schizogony in the erythrocytic stage as well as in the sporozoite stage. It is coexpressed with genes that encode the parasite motor complex, a cellular component required for parasite invasion of host cells, parasite motility and potentially cytokinesis. A targeted gene-disruption approach demonstrated that pfcdpk1 seems to be essential for parasite viability. An in vitro biochemical screen using recombinant PfCDPK1 against a library of 20,000 compounds resulted in the identification of a series of structurally related 2,6,9-trisubstituted purines. Compound treatment caused sudden developmental arrest at the late schizont stage in P. falciparum and a large reduction in intracellular parasites in Toxoplasma gondii, which suggests a possible role for PfCDPK1 in regulation of parasite motility during egress and invasion.
Assuntos
Adenina/análogos & derivados , Antimaláricos/farmacologia , Cicloexilaminas/farmacologia , Regulação Enzimológica da Expressão Gênica/genética , Malária/parasitologia , Plasmodium falciparum/enzimologia , Proteínas Quinases/efeitos dos fármacos , Proteínas Quinases/genética , Proteínas de Protozoários/antagonistas & inibidores , Adenina/química , Adenina/farmacologia , Adenina/uso terapêutico , Animais , Antimaláricos/química , Antimaláricos/uso terapêutico , Células CHO , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Cricetinae , Cricetulus , Cicloexilaminas/química , Cicloexilaminas/uso terapêutico , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Células HeLa , Humanos , Estágios do Ciclo de Vida/efeitos dos fármacos , Malária/tratamento farmacológico , Malária/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Estrutura Molecular , Peso Molecular , Movimento/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Testes de Sensibilidade Parasitária , Plasmodium falciparum/crescimento & desenvolvimento , Proteínas Quinases/fisiologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/fisiologia , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/genética , Bibliotecas de Moléculas Pequenas , Estereoisomerismo , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
The genetic background of a patient determines in part if a person develops a mild form of malaria and recovers, or develops a severe form and dies. We have used a mouse model to detect genes involved in the resistance or susceptibility to Plasmodium berghei malaria infection. To this end we first characterized 32 different mouse strains infected with P. berghei and identified survival as the best trait to discriminate between the strains. We found a locus on chromosome 6 by linking the survival phenotypes of the mouse strains to their genetic variations using genome wide analyses such as haplotype associated mapping and the efficient mixed-model for association. This new locus involved in malaria resistance contains only two genes and confirms the importance of Ppar-gamma in malaria infection.
Assuntos
Loci Gênicos/genética , Genoma/genética , Malária/genética , PPAR gama/genética , Animais , Cromossomos de Mamíferos/genética , Suscetibilidade a Doenças , Haplótipos/genética , Camundongos , Camundongos Endogâmicos , Fenótipo , Plasmodium berghei/fisiologia , Análise de SobrevidaAssuntos
Núcleo Celular/metabolismo , Citoplasma/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Plasmodium falciparum/genética , Homologia de Sequência de Aminoácidos , Proteína ran de Ligação ao GTP/química , Proteína ran de Ligação ao GTP/metabolismo , Sequência de Aminoácidos , Animais , Transporte Biológico , Eritrócitos/parasitologia , Humanos , Malária Falciparum/parasitologia , Dados de Sequência Molecular , Proteínas Nucleares/genética , Plasmodium falciparum/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Proteína ran de Ligação ao GTP/genéticaRESUMO
A fundamental problem in systems biology and whole genome sequence analysis is how to infer functions for the many uncharacterized proteins that are identified, whether they are conserved across organisms of different phyla or are phylum-specific. This problem is especially acute in pathogens, such as malaria parasites, where genetic and biochemical investigations are likely to be more difficult. Here we perform comparative expression analysis on Plasmodium parasite life cycle data derived from P. falciparum blood, sporozoite, zygote and ookinete stages, and P. yoelii mosquito oocyst and salivary gland sporozoites, blood and liver stages and show that type II fatty acid biosynthesis genes are upregulated in liver and insect stages relative to asexual blood stages. We also show that some universally uncharacterized genes with orthologs in Plasmodium species, Saccharomyces cerevisiae and humans show coordinated transcription patterns in large collections of human and yeast expression data and that the function of the uncharacterized genes can sometimes be predicted based on the expression patterns across these diverse organisms. We also use a comprehensive and unbiased literature mining method to predict which uncharacterized parasite-specific genes are likely to have roles in processes such as gliding motility, host-cell interactions, sporozoite stage, or rhoptry function. These analyses, together with protein-protein interaction data, provide probabilistic models that predict the function of 926 uncharacterized malaria genes and also suggest that malaria parasites may provide a simple model system for the study of some human processes. These data also provide a foundation for further studies of transcriptional regulation in malaria parasites.