Figure 1.

Schematic representation of integrin αvβ8–mediated TGF-β activation in nonglomerular (A) and glomerular (B and C) cells. A: In nonglomerular cells, integrin αvβ8–bound latent TGF-β is normally activated by MT1-MMP. B: In contrast, in the glomerulus of the kidney, lack of MT1-MMP expression by mesangial cells prevents integrin αvβ8–mediated TGF-β activation. C: Deletion of the integrin β8 subunits results in increased release of activated TGF-β by mesangial cells, which modulates glomerular endothelial cell apoptosis. RGD, arginine–glycine–aspartic acid.