Fibronectin

Fibronectin is an extracellular matrix protein that helps cells attach to the matrix by acting as a "linker" that binds to a cell-surface integrin molecule on one end and to a matrix component (such as collagen) on the other end. Fibronectin proteins are composed of a linear arrangement of repeating stuctural molecules that are classed into domains referred to as fibronectin repeats. The exact order of these repeats varies due to alternative splicing.