The intracellular trafficking of proteins in Plasmodium falciparum-infected erythrocytes - A review

Durante a invasäo de merozoitos nos eritrócitos, proteínas do Plasmodium säo secretadas pelo parasita induzindo várias alterações nas células infectadas do hospedeiro. Entre essas alterações está a habilidade dessas células de aderir ao endotélio vascular, e assim escapar da destruiçäo no baço. O tráfego de proteínas no Plasmodium é semelhante ao de células eucarióticas em diversos aspectos, todavia, à presença de um complexo de Golgi em P. falciparum era controverso até muito recentemente. Proteínas do parasita säo secretadas através da membrama do Retículo Endoplasmático (RE), ou inseridas nele co- ou pós-traduçäo. O parasita pode ainda secretar polipeptídeos por vias independentes da via clássica RE-complexo de Golgi e possuir duas diferentes vias, representadas pelo RE e por sERA, para o destino fina do polipeptídeo. Embora bastante progresso tenha sido feito nos últimos anos, os mecanismos envolvidos na secreçäo de proteínas pelo parasita, através de diferentes membranas para atingir a superfície do eritrócito ainda näo estäo completamente elucidados.

Characterization of a Plasmodium falciparum mutant that has deleted the majority of the gametocyte-specific Pf11-1 locus

We identified a gametocyte-specific protein of Plasmodium falciparum called Pf11-1 and provide experimental evidence that this molecule is involved in the emergence of gametes of the infected erythrocyte (gametogenesis). A mutant parasite clone, which has deleted over 90% of the PF11-1 gene locus, was an important control to establish the gametocyte-specific expression of the Pf11-1. Molecular analysis of the Pf11-1 deletion indicates that it is presumably due a chromosome breakage with subsequent "healing" by the addition of telomeric heptanucleotides. Moreover, similar DNA rearrangements are observed in most of the laboratory isolates during asexual propagation in vitro

The Pf332 gene codes for a megadalton protein of Plasmodium falciparum asexual blood stages

We characterized the Plasmodium falciparum antigen 332 (Ag332) which is specifically expressed during the asexual intraerythrocytic cycle of the parasite. The corresponding Pf332 gene has been located in the subtelomeric region of chromosome 11. Furthermore, it is present in all strais so far analyzed and shows marked restriction length fragment polymorphism. Partial sequence and restriction endonuclease digestion of cloned fragments revealed that the Pf332 gene is composed of highly degenerated repeats rich is glutamic acid. Mung been nuclease digestion and Northern blot analysis suggested that Pf332 gene codes for a protein of about 700 kDa. These data were further confirmed by Western blot and immunoprecipitation of parasites extracts with an antiserum raised against a recombinant clone expressing part of the Ag332. Confocal immunofluorescence showed that Ag332 is translocated from the parasite to the surface of infected red blood cells within vesicle-like structures. In addition, Ag332 was detected on the surface of monkey erythrocytes infected with Plasmodium falciparum