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ESCRT-III CHMP2A and CHMP3 form variable helical polymers in vitro and act synergistically during HIV-1 budding.
Effantin, Grégory; Dordor, Aurélien; Sandrin, Virginie; Martinelli, Nicolas; Sundquist, Wesley I; Schoehn, Guy; Weissenhorn, Winfried.
Afiliação
  • Effantin G; Unit of Virus Host Cell Interactions, UMI 3265, Université Joseph Fourier-EMBL-CNRS, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France.
Cell Microbiol ; 15(2): 213-26, 2013 Feb.
Article em En | MEDLINE | ID: mdl-23051622
The endosomal sorting complex required for transport-III (ESCRT-III) proteins are essential for budding of some enveloped viruses, for the formation of intraluminal vesicles at the endosome and for the abscission step of cytokinesis. ESCRT-III proteins form polymers that constrict membrane tubes, leading to fission. We have used electron cryomicroscopy to determine the molecular organization of pleiomorphic ESCRT-III CHMP2A-CHMP3 polymers. The three-dimensional reconstruction at 22 Å resolution reveals a helical organization of filaments of CHMP molecules organized in a head-to-tail fashion. Protease susceptibility experiments indicate that polymerization is achieved via conformational changes that increase the protomer stability. Combinatorial siRNA knockdown experiments indicate that CHMP3 contributes synergistically to HIV-1 budding, and the CHMP3 contribution is ~ 10-fold more pronounced in concert with CHMP2A than with CHMP2B. This is consistent with surface plasmon resonance affinity measurements that suggest sequential CHMP4B-CHMP3-CHMP2A recruitment while showing that both CHMP2A and CHMP2B interact with CHMP4B, in agreement with their redundant functions in HIV-1 budding. Our data thus indicate that the CHMP2A-CHMP3 polymer observed in vitro contributes to HIV-1 budding by assembling on CHMP4B polymers.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: HIV-1 / Complexos Endossomais de Distribuição Requeridos para Transporte / Liberação de Vírus Tipo de estudo: Prognostic_studies Idioma: En Ano de publicação: 2013 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: HIV-1 / Complexos Endossomais de Distribuição Requeridos para Transporte / Liberação de Vírus Tipo de estudo: Prognostic_studies Idioma: En Ano de publicação: 2013 Tipo de documento: Article