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Spring-loaded model revisited: paramyxovirus fusion requires engagement of a receptor binding protein beyond initial triggering of the fusion protein.
Porotto, Matteo; Devito, Ilaria; Palmer, Samantha G; Jurgens, Eric M; Yee, Jia L; Yokoyama, Christine C; Pessi, Antonello; Moscona, Anne.
Afiliação
  • Porotto M; Departments of Pediatrics and of Microbiology and Immunology, Weill Medical College of Cornell University, 515 East 71st Street, 6th Floor, Box 309, New York, NY 10021, USA.
J Virol ; 85(24): 12867-80, 2011 Dec.
Article em En | MEDLINE | ID: mdl-21976650
During paramyxovirus entry into a host cell, receptor engagement by a specialized binding protein triggers conformational changes in the adjacent fusion protein (F), leading to fusion between the viral and cell membranes. According to the existing paradigm of paramyxovirus membrane fusion, the initial activation of F by the receptor binding protein sets off a spring-loaded mechanism whereby the F protein progresses independently through the subsequent steps in the fusion process, ending in membrane merger. For human parainfluenza virus type 3 (HPIV3), the receptor binding protein (hemagglutinin-neuraminidase [HN]) has three functions: receptor binding, receptor cleaving, and activating F. We report that continuous receptor engagement by HN activates F to advance through the series of structural rearrangements required for fusion. In contrast to the prevailing model, the role of HN-receptor engagement in the fusion process is required beyond an initiating step, i.e., it is still required even after the insertion of the fusion peptide into the target cell membrane, enabling F to mediate membrane merger. We also report that for Nipah virus, whose receptor binding protein has no receptor-cleaving activity, the continuous stimulation of the F protein by a receptor-engaged binding protein is key for fusion. We suggest a general model for paramyxovirus fusion activation in which receptor engagement plays an active role in F activation, and the continued engagement of the receptor binding protein is essential to F protein function until the onset of membrane merger. This model has broad implications for the mechanism of paramyxovirus fusion and for strategies to prevent viral entry.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Receptores Virais / Proteína HN / Proteínas do Envelope Viral / Proteínas Virais de Fusão / Vírus da Parainfluenza 3 Humana / Vírus Nipah / Internalização do Vírus Idioma: En Ano de publicação: 2011 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Receptores Virais / Proteína HN / Proteínas do Envelope Viral / Proteínas Virais de Fusão / Vírus da Parainfluenza 3 Humana / Vírus Nipah / Internalização do Vírus Idioma: En Ano de publicação: 2011 Tipo de documento: Article