Dystroglycan and laminins: Glycoconjugates involved in branching epithelial morphogenesis

Branching epithelial morphogenesis is crucial for the development of several organs, such as lung, submandibullar gland, mammary gland, tooth, pancreas, and kidney. During early embryogenesis, these organs are composed of a small epithelial rudiment surrounded by mesenchymal cells. Interactions between the two tissue compartments induce growth and branching of the epithelium into the mesenchyme. In each tissue, the epithelial branching has tissue-specific features, but there are many similarities both at the morphological and molecular level. Basement membrane components such as laminin have been implicated in the regulation of epithelial morphogenesis. Here data are reviewed that suggest that interactions between laminin-1 and other basement membrane components and the cell surface are important for epithelial morphogenesis in the kidney, lung, and salivary gland.