integrin alpha4beta1 is a FIBRONECTIN and VCAM-1 receptor present on lymphocytes; monocytes; eosinophils; NK cells and thymocytes. It is involved in both cell-cell and cell- extracellular matrix adhesion and plays a role in inflammation, hematopoietic cell homing and immune function, and has been implicated in skeletal MYOGENESIS; neural crest migration and proliferation, lymphocyte maturation and morphogenesis of the placenta and heart.