Fibronectin: A review of its structure and biological activity

In 1948, MORRISON and co-workers demonstrated the co-precipitation of a high molecular weight plasma protein with cryofibrinogen following incubation in the cold 1. This protein was designated cold insoluble globulin (CIG). In 1973-1974 several laboratories using various techniques, made the independent observation that fibroblasts growing in tissue culture possessed a high molecular weight protein on their cell surface 2-7. CIG and this cell surface associated protein were established by immunological criteria to be identical a and subsequently by biochemical analysis to be very similar but to possess subtle differences in structure and function (see below). Fibronectin (Fn) is a widely accepted designation for both plasma and cell associated forms of this protein 9 and will be used throughout this review to represent both states of the protein. Differences between the two forms will be indicated where appropriate. Several reviews 1° 13 have extensively covered Fn and some degree of overlap has been unavoidable. However, the rapidly expanding attention and research effort devoted to this protein has allowed us to focus on more recent information and insights.