1. Evidence for expression of a Ras-like and a stage specific GTP binding homologous protein by Plasmodium falciparum
- Author
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Pierre Ambroise-Thomas, Valérie Bracchi, Jacques Thélu, and Josette Burnod
- Subjects
Cholera Toxin ,GTP' ,G protein ,Molecular Sequence Data ,Plasmodium falciparum ,Protozoan Proteins ,Guanosine ,medicine.disease_cause ,Pertussis toxin ,chemistry.chemical_compound ,GTP-Binding Proteins ,Heterotrimeric G protein ,Reproduction, Asexual ,parasitic diseases ,medicine ,Animals ,Humans ,Amino Acid Sequence ,Virulence Factors, Bordetella ,biology ,Cholera toxin ,Cell Biology ,biology.organism_classification ,Molecular biology ,Blot ,Pertussis Toxin ,chemistry ,ras Proteins ,Signal Transduction - Abstract
Plasmodium falciparum, the parasite responsible for the most severe form of malaria, undergoes an asexual multiplication in man and a sexual one in mosquito. The asexual cycle can be reproduced in vitro. The present work reports the isolation of a small guanosine triphosphate-binding protein in Plasmodium falciparum extracts. This protein, a 21,000 Mr Ras-like molecule, was revealed by western blotting in each stage of the intraerythrocytic asexual life cycle. Conversely, a 46,000 Mr Gα subunit of a heterotrimeric GTP-binding protein was found to be expressed during a short period from mature schizonts to free merozoites. In order to provide additional evidence for the presence of these GTP-binding proteins in Plasmodium falciparum cultures and also to determine the kinetics, we tested two toxins that are involved in the cellular signalling transduction. We observed that pertussis toxin increases P. falciparum growth, whereas cholera toxin induces crisis forms, and subsequent parasite death within the following 24 h.
- Published
- 1994