title: The GTPase Rab3b/3c-positive recycling vesicles are involved in cross-presentation in dendritic cells.
abstract: Antigen cross-presentation in dendritic cells is a complex intracellular membrane transport process, but the underlying molecular mechanisms remain to be thoroughly investigated. In this study, we examined the effect of siRNA-mediated knockdown of 57 Rab GTPases, the key regulators of membrane trafficking, on antigen cross-presentation. Twelve Rab GTPases were identified to be associated with antigen cross-presentation, and Rab3b/3c was indicated to be colocalized with MHC class I molecules at perinuclear tubular structure. Tracing with fluorescence protein-tagged beta(2)-microglobulin demonstrated that the MHC class I molecules were internalized from the plasma membrane to Rab3b/3c-positive compartments, which were also colocalized with the internalized transferrin. Moreover, depletion of Rab3b/3c strongly reduced the fast phase recycling rate of transferrin receptors. Furthermore, the Rab3b/3c-positive compartments were colocalized with a fraction of Rab27a at a juxtaposition of phagosomes. Together, these data demonstrate that Rab3b/3c-positive recycling vesicles are involved in and may constitute one of the recycling compartments in exogenous antigen cross-presentation.
authors.affiliation: Institute of Immunology, People's Liberation Army, Third Military Medical University, Chongqing 400038, China.
authors.forename: Liyun
authors.initials: L
authors.lastname: Zou
authors.forename: Jingran
authors.initials: J
authors.lastname: Zhou
authors.forename: Jinyu
authors.initials: J
authors.lastname: Zhang
authors.forename: Jingyi
authors.initials: J
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.forename: Linlin
authors.initials: L
authors.lastname: Chai
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.forename: Liqi
authors.initials: L
authors.lastname: Li
authors.forename: Zhunyi
authors.initials: Z
authors.lastname: Xie
authors.forename: Hongli
authors.initials: H
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wan
authors.forename: Yuzhang
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000502:physiology*; D001693:Biological Transport, Active; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism* / Q000648:ultrastructure; D011992:Endosomes / Q000276:immunology / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D034741:RNA, Small Interfering / Q000235:genetics; D020692:rab3 GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D015395:Histocompatibility Antigens Class I; D034741:RNA, Small Interfering; C492131:RAB3B protein, human; C116710:RAB3C protein, human; C116709:Rab3b protein, mouse; C486479:Rab3c protein, mouse; D020692:rab3 GTP-Binding Proteins