Examples of structural proteins include collagen, elastin, proteoglycans, and fibronectin.
Collagen plays many diverse rolls in physiology, from providing strength to tendons and ligaments, serving as the matrix for bone deposition, and forming the filtration membranes in the glomeruli of kidneys.

Elastin is found in the walls of blood vessels and in ligaments.

Consisting of about 95% polysaccharide (glycosaminoglycans), 5% protein, proteoglycans serve as the ground substance (extracellular medium) of many types of connective tissue.

The adhesive cell surface proteins fibronectin and laminin bind the external faces of the cell membranes to collagen and other components of the extracellular matrix.