Figure 6.

The effect of ephrins on integrin-mediated signaling and migration. A, B, pFAK immunostaining in nontreated controls (A) and clustered ephrinA5-treated cells (B). Addition of clustered ephrinA5 to Schwann cells plated on laminin reduces pFAK levels. Scale bar, 75 μm. C, D, Immunostaining of Schwann cells labeled for p75 in contact with GFAP-labeled astrocytes (C) and the corresponding phosphorylated FAK staining (D). Schwann cells in contact with hypertrophied astrocytes have decreased pFAK levels compared with control noncontacting Schwann cells. The yellow arrow points to a Schwann cell in contact with astrocytes and the white arrow to a noncontacting Schwann cell. Scale bar, 25 μm. E, Addition of integrin activating Mn²⁺ (500 μm) to Schwann cells migrating in the presence of clustered ephrinA5 reverses the inhibitory effect of ephrinA5 on migration. n = 5; ANOVA, *p < 0.05. F, G, Images of the migration assay after addition of clustered ephrinA5 in the absence (F) and presence (G) of Mn²⁺. H, VAV2 knockdown in Schwann cells abolishes the inhibitory effect of ephrinA5 on Schwann cell migration on laminin. n = 3; ANOVA, *p < 0.05. I, J, Images of Schwann cell migration on laminin in the presence of clustered ephrinA5 in control siRNA (I) and VAV2 siRNA (J) treated cells.