title: Interaction between cFLIP and Itch, a ubiquitin ligase, is obstructed in Trypanosoma cruzi-infected human cells.
abstract: Death receptor-mediated host cell apoptosis, a defense strategy for elimination by the immune system of parasite-infected cells, is inhibited by Trypanosoma cruzi, the causative agent of Chagas' disease. It has previously been reported by us that, in infected cells, T. cruzi upregulates and exploits cFLIP(L), a mammalian inhibitor of death receptor signaling. Here it is shown that ubiquitination of cFLIP(L,) leading to proteasomal degradation, is inhibited in parasite-infected cells. The extent of expression of Itch, a protein thought to be an ubiquitin ligase for cFLIP(L), was found to be equivalent in T. cruzi-infected and in uninfected cells. However, co-immunoprecipitation analysis showed that the interaction between cFLIP(L) and Itch is strongly inhibited in T. cruzi-infected cells. This unique parasite strategy, which has not been reported in any other pathogen-infected cells, may allow the host cell to accumulate cFLIP(L), eventually resulting in the inhibition of apoptosis of T. cruzi-infected cells.
authors.affiliation: Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Murata
authors.forename: Muneaki
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoki
mesh_terms: D000818:Animals; D017209:Apoptosis; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000378:metabolism*; D014355:Chagas Disease / Q000469:parasitology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D007976:Leupeptins / Q000494:pharmacology; D061988:Proteasome Inhibitors; D012097:Repressor Proteins / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000469:parasitology*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D061988:Proteasome Inhibitors; D012097:Repressor Proteins; C432966:ITCH protein, human; D044767:Ubiquitin-Protein Ligases; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde