HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (Papers in Press[PDF]) Supplementary Videos All Versions of this Article: vir.0.014159-0v1 90/12/2902    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Zamudio-Meza, H. Articles by Meza, I. PubMed PubMed Citation Articles by Zamudio-Meza, H. Articles by Meza, I. Agricola Articles by Zamudio-Meza, H. Articles by Meza, I.

Rac1 and Cdc42 GTPases cross-talk regulates formation of filopodia required for Dengue virus type-2 entry into HMEC-1 cells

¹ Centro de Investigación y de Estudios Avanzdos del IPN. México DF, Mexico;
² Unidad de Investigación Biomédica, Centro Médico Nacional La Raza-IMSS. Mexico

³ E-mail: imeza{at}cinvestav.mx

Infection with Dengue virus type-2 (DENV-2) begins with virus adherence to cell surface receptors. In endothelial cells (HMEC-1), a cell model for DENV-2 infection, 5β3 integrin has been identified as a putative receptor for the virus. Previous work had suggested that the actin cytoskeleton of HMEC-1 cells plays an important role in virus entry and infection. In the present work, fixed and living HMEC-1 cells expressing EGFP-actin were monitored for actin reorganization after virus inoculation, utilizing fluorescence and time lapse microscopy. Cell infection and production of infective viruses were quantified using an anti-E viral protein antibody and by the number of pfu/ml. Specific drugs that antagonize actin organization and regulate actin-signaling pathways, as well as the expression of dominant negative Rac1, Cdc42 proteins, were tested in viral adhesion and infection assays. Disorganization of actin precluded infection, while microtubule depolymerization had no effect. Activation of Rac1 and Cdc42 signaling, occurring upon virus binding, induced reorganization of actin to form filopodia in the cellular periphery. Formation of filopodia was a requirement for virus entry and further cell infection. Expression of dominant negative proteins of Rac1 and Cdc42 confirmed the role of these GTPases in the actin reorganization required to form filopodia. In addition, inhibition of the ATPase activity of myosin II greatly decreased infection, suggesting its participation in filopodial stability. We show here, for the first time, that internalization of DENV-2 into endothelial cells requires viral induction of dynamic filopodia regulated by Rac1 and Cdc42 cross talk and myosin II motor activities.

Received 5 June 2009; accepted 21 August 2009.