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Fig. 5. Dose-dependent inhibition of cell adhesion and spreading by surface-bound
ephrin-A5. (A) Capacity of Protein A-coated 96-well plates for Ephrin-A5 Fc
(
) and of Protein A-bound ephrin-A5 for EphA3 (
). Ephrin-A5 Fc was
applied at indicated concentrations and bound protein in the supernatant was
estimated by Biacore analysis. To confirm the competence of tethered ephrin-A5
to interact with the receptor, the nonbound fraction of EphA3 (2 µg/ml)
after incubation on ephrin-A5-coated wells was determined by Biacore analysis.
The amount of bound EphA3 estimated from this assay is shown (
). (B) 293T
cells, transiently transfected with w/t or mutant EphA3, and pEGFP-actin were
plated (5x104cells/well) onto wells coated with ephrinA5-Fc
at the indicated densities (ng/mm2). After 5 hours, adherent cells
were fixed with 4% paraformaldehyde and examined by fluorescence microscopy.
Sections of w/t EphA3-transfected cells are shown. Bar, 20 µm. (C)
Following microscopy, adherent cells were quantified using crystal violet
staining. Cell attachment is expressed as a percentage (mean±s.d. from
three independent assays) relative to adhesion seen on non-ephrin-A5-coated
wells; [UNK], w/t EphA3;
, Y596F EphA3;
, Y602F EphA3;
,
Y779F EphA3;
, Y596F+Y602F EphA3.