What the Lung Has Taught Us about Latent TGF-β Activation

In the December 2007 issue of the Journal, Koth and colleagues show that the multifunctional cytokine transforming growth factor (TGF)-β can claim influence over yet one more process: surfactant homeostasis (1). The key to this discovery was the observation that mice lacking an important lung epithelium integrin, αvβ6, which activates the latent form of TGF-β, have foamy-appearing alveolar macrophages. This result adds to a growing list of TGF-β functions in the lung that are downstream of αvβ6-mediated TGF-β activation.