Specific Interactions between Human Integrin αvβ3and Chimeric Hepatitis B Virus Core Particles Bearing the Receptor-Binding Epitope of Foot-and-Mouth Disease Virus

Abstract

Purified integrin alpha v beta 3 was used in solid-phase binding studies with chimeric hepatitis B cores which carry the RGD-containing loop of VP1 protein of the foot-and-mouth disease virus (FMDV). High levels of specific binding between the integrin and the particles were detected by enzyme-linked immunosorbent assays. The binding was Mn2+ cation dependent and could be competed with fibronectin, vitronectin, and the peptide GRGDSPK. Particles in which the RGD motif had been mutated to RGE failed to bind, indicating that the chimeric cores bound specifically to the ligand binding site of integrin alpha v beta 3. Electron micrographs showed several individual alpha v beta 3 molecules bound to the surface of each chimeric particle. Collectively, these data constitute firm evidence that the RGD-containing loop of FMDV is critical for binding to alpha v beta 3 and provide support for identification of alpha v beta 3 as a potential cellular receptor for FMDV.

An Adenovirus Vector with Genetically Modified Fibers Demonstrates Expanded Tropism via Utilization of a Coxsackievirus and Adenovirus Receptor-Independent Cell Entry Mechanism

“…In some of these instances, this tripeptide has been shown to play an important role in the process of viral infection by mediating primary or secondary interactions between the virion and cell surface-localized integrins. Furthermore, recent studies showed that genetic incorporation of the RGD-containing sequences into chimeric hepatitis B cores (11,36), poliovirus particles (30), bacteriophage fd (19,20), and human Ad virions (44) allows specific interaction of these viral particles with cellular integrins, thereby resulting in binding of aforementioned structures to cell surface.…”

“…ELISA. Solid-phase binding assay was performed by a method previously described by Sharma et al (36). Briefly, purified fiber proteins or Ad virions were diluted in 50 mM carbonate-bicarbonate buffer, pH 9.6, to a concentration of 10 g of protein per ml, and 100-l aliquots were added to the wells of a 96-well Nunc-Maxisorp enzyme-linked immunosorbent assay (ELISA) plate.…”

The Eighth FIII Domain of Human Fibronectin Promotes Integrin α5β1 Binding via Stabilization of the Ninth FIII Domain

“…Purification of Integrin ␣ 5 ␤ 1 -Integrin ␣ 5 ␤ 1 was purified from human placenta as described previously (21), with some modifications. Briefly, a placenta was homogenized in 200 ml ice-cold lysis buffer (50 mM Tris-HCl, pH 7.4, 1 mM MgCl 2 , 1 mM MnCl 2 , 1 mM CaCl 2 , 150 mM NaCl, 1% Triton X-100) containing sodium vanadate (1 mM), leupeptin (10 g ml Ϫ1 ), aprotinin (10 g ml Ϫ1 ), and phenylmethylsulfonyl fluoride (1 mM).…”

Attenuation of Murray Valley Encephalitis Virus by Site-Directed Mutagenesis of the Hinge and Putative Receptor-Binding Regions of the Envelope Protein

“…The second mutant, E-390 (D3E), was constructed for two reasons: first, because it represented a conservative amino acid change, and second, because other flaviviruses such as West Nile virus (WNV) (72) and KUN (15) possess an RGE as opposed to an RGD motif in this region of the protein. Substitution of a Glu residue at the third position of an RGD motif has been shown to abolish RGD-dependent integrin binding by a range of viruses, including FMDV (44), chimeric hepatitis B virus (64), and echovirus type 9 (76). The last mutant, E-390 (D3Y), was constructed because it represented the substitution of a large hydrophobic amino acid residue into a strongly hydrophilic region of the protein.…”