ABSTRACT
The most relevant features of fibronectin are the several structural domains with binding specificities for macromolecules and for cells. Cell surface receptors for fibronectin have been identified and/or isolated from a number of cell types including fibroblasts, hepatocytes, monocytes, and monocytoid cell lines, erythroblasts, and other hematopoietic cells. Structural studies of the fibronectin receptors of hematopoietic cells have been limited. This chapter suggests that repletion of fibronectin, given in the form of cryoprecipitate or purified protein, may normalize theactivity of mononuclear phagocytes. The region of fibronectin primarily involved in the binding to cells is located toward the center of the molecule and contains the RGD sequence. The cascade of events which ensues following tissue injury involves monocytes and macrophages at several critical steps. Fibronectin is a substrate for monocyte attachment at sites of injury and inflammation. It is also becoming clear that proteolytic fragments of fibronectin may play a role in mononuclear phagocyte function.
