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Characterization of Synaptotagmin XI in macrophages

Arango Duque, Guillermo; Fukuda, Mitsunori; Descoteaux, Albert . Characterization of Synaptotagmin XI in macrophages In: 11ième Symposium Annuel de Parasitologie Moléculaire du Québec, 7-8 juin 2011, Université McGill.

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Résumé

Synaptotagmins (Syts) are a group of type-I membrane proteins that regulate vesicle docking and fusion in processes such as the exocytosis of synaptic vesicles and hormones, and phagocytosis. All Syts possess a conserved transmembrane domain, and two tandem Ca2+-binding C2 domains. Syts IV and XI, however, possess a conserved serine in their C2A domain that precludes them from binding to Ca2+ and phospholipids. SytXI is thought to inhibit vesicle fusion or to mediate vesicle trafficking processes independent of Ca2+. As of today, a function has not been ascribed to SytXI. We show that, in murine macrophages, SytXI localizes to transferrin receptor 1-containing recycling endosomes. SytXI was found to be recruited early to phagosomes. Nonetheless, SytXI recruitment was absent in Leishmania promastigote phagosomes. We demonstrate that SytXI was degraded by L. donovani and L. major promastigotes, but not amastigotes. Degradation occurred shortly after infection, and it was dependant on the gp63 metalloprotease in the case of L. major. Real-time quantitative reverse transcription PCR (QPCR) data showed that Leishmania promastigotes lowered SytXI mRNA levels rapidly but temporarily. Also, SytXI coimmunoprecipitated with Syntaxin 13, a soluble NSF-attachment protein receptor (SNARE) involved in the early stages of phagocytosis and in protein and cholesterol trafficking. Altogether, our data point to a possible role for SytXI in phagocytosis, vesicle trafficking and in Leishmania infection. Presently, siRNA-mediated knockdown of SytXI is being used to study the role of SytXI in cytokine secretion

Type de document: Document issu d'une conférence ou d'un atelier
Informations complémentaires: Présentation par affiche
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Centre: Centre INRS-Institut Armand Frappier
Date de dépôt: 03 mai 2018 15:13
Dernière modification: 03 mai 2018 15:13
URI: http://espace.inrs.ca/id/eprint/7109

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