However, recent evidence has shown that Marfan's results from mutations in the extracellular protein, fibrillin , which is an integral constituent of the non-collagenous microfibrils of the extracellular matrix. The role of fibronectins is to attach cells to a variety of extracellular matrices. Fibronectin attaches cells to all matrices except type IV that involves laminin as the adhesive molecule. Fibronectins are dimers of 2 similar peptides. At least 20 different fibronectin chains have been identified that arise by alternative RNA splicing of the primary transcript from a single fibronectin gene.
All basal laminae contain a common set of proteins and GAGs.
These are type IV collagen , heparan sulfate proteoglycans , entactin and laminin . The basal lamina is often refered to as the type IV matrix . Each of the components of the basal lamina is synthesized by the cells that rest upon it. Laminin anchors cell surfaces to the basal lamina. V fibronectin heparan sulfate and heparin integrin quiescent fibroblasts VI fibronectin heparan sulfate Iitegrin quiescent fibroblasts back to the top Return to Medical Biochemistry Page Michael W. King, Ph.