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Advances in Virology
Volume 2012 (2012), Article ID 547530, 9 pages
http://dx.doi.org/10.1155/2012/547530
Review Article

Endocytosis of Integrin-Binding Human Picornaviruses

1Department of Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland
2Degree Program in Biotechnology and Food Technology, Turku University of Applied Sciences, Lemminkäisenkatu 30, 20520 Turku, Finland
3Joint Biotechnology Laboratory, University of Turku, Tykistökatu 6a, 20520 Turku, Finland

Received 10 August 2012; Revised 21 October 2012; Accepted 5 November 2012

Academic Editor: Christopher M. Wiethoff

Copyright © 2012 Pirjo Merilahti et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Picornaviruses that infect humans form one of the largest virus groups with almost three hundred virus types. They include significant enteroviral pathogens such as rhino-, polio-, echo-, and coxsackieviruses and human parechoviruses that cause wide range of disease symptoms. Despite the economic importance of picornaviruses, there are no antivirals. More than ten cellular receptors are known to participate in picornavirus infection, but experimental evidence of their role in cellular infection has been shown for only about twenty picornavirus types. Three enterovirus types and one parechovirus have experimentally been shown to bind and use integrin receptors in cellular infection. These include coxsackievirus A9 (CV-A9), echovirus 9, and human parechovirus 1 that are among the most common and epidemic human picornaviruses and bind to αV-integrins via RGD motif that resides on virus capsid. In contrast, echovirus 1 (E-1) has no RGD and uses integrin α2β1 as cellular receptor. Endocytosis of CV-A9 has recently been shown to occur via a novel Arf6- and dynamin-dependent pathways, while, contrary to collagen binding, E-1 binds inactive β1 integrin and enters via macropinocytosis. In this paper, we review what is known about receptors and endocytosis of integrin-binding human picornaviruses.