Extracellular matrix (ECM) is an important determinant of cellular behavior, regulating cellular adhesion, cellular migration, cellular proliferation, and cellular differentiation. Increasingly, it has become appreciated that certain of these actions of ECM derive from its ability to sequester and modulate the activity of specific growth factors [1]. Of all of the growth factors, none has been found to have the diversity of effects on ECM ascribed to transforming growth factor-β (TGF-β). This peptide plays a critical role not only in synthesis and degradation of ECM but also in response of cells to ECM mediated through integrin receptors; moreover, specific components of the ECM, in turn, can both deliver TGF-β and regulate its activity [reviewed in 2–4].