Integrins and Their Extracellular Matrix Ligands in Lymphangiogenesis and Lymph Node Metastasis
Figure 3
The integrin family of matrix receptors in lymphangiogenesis. (a) Integrin subunits divided by their binding partners (connecting lines) and ligand-binding preferences (shaded areas). (b) Structure of integrin adhesions. Integrins link the extracellular matrix to the intracellular actin cytoskeleton through structural adaptor proteins. Recruitment of signaling proteins activates pathways that regulate gene expression (e.g., MAP kinases) and cytoskeletal reorganization (Rho GTPases). (c) Expression of the integrin α9β1 and its EDA-fibronectin ligand are required for proper lymphatic valve development. While α6β1 and α9β1 are implicated in tumor angiogenesis, only α4β1 has been shown to be upregulated in lymphangiogenic vessels, to mediate LEC migration and tube formation in culture, and to be required for tumor-associated lymphangiogenesis.
