Integrin signaling in leukocytes: lessons from the alpha6beta1 integrin

The adhesive interactions of leukocytes with basement membrane components and other extracellular matrix (ECM) proteins are mediated largely by the integrin family of receptors. These interactions can be regulated by various effector molecules including chemokines, growth factors, and other cell surface proteins by a mechanism termed inside-out signaling of integrin function. On engagement by their ligands, integrins activate a wide range of signaling pathways that regulate a broad array of leukocyte functions such as chemotaxis, cytokine responsiveness, phagocytosis, and gene expression. This review highlights recent advances in the understanding of integrin signaling in leukocytes with an emphasis on our own work on the alpha6beta1 integrin, the major laminin receptor expressed by these cells.