Heparan Sulfate-Binding Foot-and-Mouth Disease Virus Enters Cells via Caveola-Mediated Endocytosis

Abstract

Foot-and-mouth disease virus (FMDV) utilizes different cell surface macromolecules to facilitate infection of cultured cells. Virus, which is virulent for susceptible animals, infects cells via four members of theFoot-and-mouth disease virus (FMDV) is the type species of the genus Aphthovirus of the family Picornaviridae. The virus is the cause of a highly contagious disease of cloven-hoofed livestock, which is characterized by vesicular lesions in the mouth and on the feet, teats, and nares (see reference 31 and references therein). It has been well established that, via a conserved Arg-Gly-Asp (RGD) sequence in the ␤G-to-␤H (G-H) loop of VP1 (6,26,41,49), the virus utilizes four members of the ␣ V subgroup of cellular integrins (␣ V ␤ 1 , ␣ V ␤ 3 , ␣ V ␤ 6 , and ␣ V ␤ 8 ) as receptors in tissue culture (12,21,34,37,38,54).In addition to cellular integrins, FMDV is also able to utilize alternative membrane molecules as receptors. The first evidence of this was presented in reports that found antibody-complexed virus was able to bind to Fc receptors and that this binding led to internalization and viral replication (7,47,49). This work was expanded to develop an artificial receptor by fusing a single-chain monoclonal antibody against FMDV (46) to the intercellular adhesion molecule 1 (ICAM-1), engineering a receptor designed to allow virus with an altered receptor binding site with which to attach and replicate in cells (67). Finally, it was demonstrated that some FMDV serotypes, when adapted to tissue culture, gain the ability to utilize cell surface heparan sulfate (HS) as a viral receptor (2, 35, 45, 54), resulting in the attenuation of virulence in host species (70). The interactions between these virions and HS have recently been delineated by crystallographic analyses (19,(27)(28)(29). These data, along with recent evidence that FMDV interaction with soluble ␣ V ␤ 6 integrin does not result in structural alterations to the virion (22), suggest that the viral receptor plays a role only in docking and internalizing the virion. However, in spite of the ability of the virion to utilize alternative receptors, the available evidence suggests that the integrin receptor is the only one involved in viral pathogenesis in the susceptible host (52,54,68; V. O'Donnell, A. Koser, D. Gregg, and B. Baxt Recently, studies of the entry of FMDV into cultured cells have been initiated. Results from both our laboratory and that of Jackson and colleagues have demonstrated that integrinbinding FMDV types A and O utilize a clathrin-dependent mechanism to infect cells, trafficking through early endosomes into recycling endosomes (13,58). It is within these endosomes that the virion breaks down (3-5, 16, 51), releasing the viral genome to the cytosol. More recently, Martin-Acebes et al.(44) also demonstrated the involvement of a clathrin-dependent mechanism in productive FMDV type C endocytosis. It was of interest to us to determine the mechanism of entry for FMDV when the virus uses a receptor other than an integrin, for example, ...

Foot-and-Mouth Disease Virus Nonstructural Protein 2C Interacts with Beclin1, Modulating Virus Replication

“…These mutated 2C proteins were assessed for their ability to bind Beclin1 utilizing the yeast two-hybrid system. 2C proteins containing mutations in areas 15,16,17,19,20,29,33 to 40, and 42 were unable to bind Beclin1 (Fig. 10A).…”

The Spike Protein VP4 Defines the Endocytic Pathway Used by Rotavirus To Enter MA104 Cells

“…The example of variant Nar3 is not unprecedented, since single or a few amino acid changes in echovirus (46), enterovirus (47)(48)(49), coxsackievirus (50)(51)(52), and foot-and-mouth disease virus (53)(54)(55) have been shown to be sufficient to alter the receptor specificity and the endocytic mode of entry of these viruses. In the case of rotaviruses, however, it seems that the cell surface molecule used to attach to cells does not by itself determine the type of endocytosis pathway employed for virus cell entry.…”

A Single Amino Acid Substitution in the Capsid of Foot-and-Mouth Disease Virus Can Increase Acid Lability and Confer Resistance to Acid-Dependent Uncoating Inhibition

“…In addition, internalized FMDV particles colocalize with markers from early and recycling endosomes (8,51,52) and FMDV infection is reduced by expression of a dominant negative mutant of Rab5 (33), suggesting that FMDV may release its genome from these compartments.…”

“…FMDV isolates interacting with integrins gain entry into the cell following clathrin-mediated endocytosis (8,39,52). On the other hand, it has been described that a genetically engineered HS-binding mutant uses caveolae to enter into cultured cells (51). After internalization, FMDV must release its genomic RNA molecule of positive polarity into the host cell cytoplasm to establish a productive infection.…”