Fig. 8: SAFV binds to the RGD-binding site of integrin αVβ8 via an alternative sequence rather than an RGD-like sequence. | Nature Communications

Fig. 8: SAFV binds to the RGD-binding site of integrin αVβ8 via an alternative sequence rather than an RGD-like sequence.

From: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

Fig. 8: SAFV binds to the RGD-binding site of integrin αVβ8 via an alternative sequence rather than an RGD-like sequence.The alternative text for this image may have been generated using AI.

a Viral infection analysis using integrin β8 mutants. BHK-21 cells expressing the human integrin β8 mutants (∆SDL, Y172N, and I208R) were inoculated with SAFV-3. After 2 days, virus titers were determined using the TCID50 assay. Human integrin β3 was the negative control. The dotted line indicates the limit of detection. The right panel shows the results of western blot analysis of integrin β8 mutants and integrin β3 expression in BHK-21 cells. b Alignment of the amino acid sequences of puff A on VP2 of SAFV-3 (left panel) and CD loop I on VP1 of SAFV-2 (right panel). RGD-like sequences are highlighted. c Infection blocking assay using RGD peptide. Left panel: HeLaN-∆SLC cells were pretreated with 10 or 100 μg of GRGDS, GRADS, or GRAES peptide at 4 °C for 30 min and then incubated with SAFV-3/UnaG virus for an additional 60 min. Right panel: HeLaN-∆SLC cells were pretreated with 10 or 100 μg of GRGDS, GRLDS, or GRAES peptide for 30 min and then incubated with SAFV-2/UnaG virus for an additional 60 min. GRGDS and GRAES peptides were positive and negative controls, respectively. The number of UnaG-positive cells at 14 h post-infection was counted using ImageJ software. d Schematic illustration of mutagenesis in RGD-like sequence. The mutated amino acid residues are highlighted. e HeLaN-∆SLC∆B8, HeLaN-∆SLC, and HeLaN-∆SLC + human AVB8 cells were infected with tenfold serial dilutions of mutant viruses carrying mutations in the RGD-like sequences, and viable cells were stained with crystal violet. Primary progeny virus produced from BHK cells transfected with infectious RNA (P-0 virus) was used. Bar graphs in (a and c) represent means with s.d. (n = 3 in (a); n = 9 peptide-free and n = 3 peptide-added samples in (c)). Statistical significance was determined using a one-way ANOVA with Dunnett’s multiple comparison test. **, P < 0.01, n.s. not significant. Statistical comparisons in (c) were made between peptide-free and peptide-added samples. All data are representative of two independent experiments. Source data are provided as a Source Data file.

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