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Theses

CD81 et microdomaines enrichis en tétraspanines :
rôle dans l'infection des hépatocytes par Plasmodium.

Abstract : Infection of hepatocytes by Plasmodium sporozoites is a prerequisite for initiation of malaria. Still, the molecular mechanisms involved during sporozoite invasion remain poorly characterized. We found that CD81, a host membrane protein belonging to the tetraspanin superfamily, is required for infection of hepatocytes by Plasmodium falciparum, Plasmodium yoelii and in certain circumstances Plasmodium berghei sporozoites. Expression of CD81 in human hepatocarcinoma HepG2 cells is sufficient to confer susceptibility to P. yoelii but not P. falciparum sporozoites, suggesting that other molecules are specifically required for infection by the human parasite. Tetraspanins associate extensively with one another and with other membrane proteins to form specific membrane microdomains, called tetraspanin-enriched microdomains, which are distinct from conventional lipid rafts. Our results demonstrate that membrane cholesterol contributes not only to the localization of CD81 into tetraspanin-enriched microdomains but also to CD81-dependent infection by Plasmodium sporozoites. So far, we found no evidence for a direct interaction between CD81 and sporozoites, suggesting that CD81 does not act as a receptor for the parasite but is rather involved indirectly. EWI-F and EWI-2, two membrane proteins associated with CD81 in hepatocytes, are not directly involved during sporozoite infection. On the contrary, expression of EWI-F has a negative effect on infection, which could result from a reorganization of tetraspanin-enriched microdomains or from a competition with another CD81 partner. A still unidentified molecule associated with CD81 may thus play an essential role during infection by Plasmodium sporozoites, possibly by acting as a receptor.
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https://tel.archives-ouvertes.fr/tel-00011596
Contributor : Olivier Silvie <>
Submitted on : Monday, February 13, 2006 - 4:03:22 PM
Last modification on : Wednesday, December 9, 2020 - 3:12:05 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 4:23:45 PM

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  • HAL Id : tel-00011596, version 1

Citation

Olivier Silvie. CD81 et microdomaines enrichis en tétraspanines :
rôle dans l'infection des hépatocytes par Plasmodium.. Biologie cellulaire. Université Pierre et Marie Curie - Paris VI, 2006. Français. ⟨tel-00011596⟩

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