Elastin

Elastin is part of connective tissue. It is an elastic protein which allows many tissues in the body to go back to their shape after stretching or contracting. Elastin helps skin return to its original position when handled. Elastin is also used in places where mechanical energy is stored. 
Elastin is important in blood vessels because it helps blood to flow. It is common in large elastic blood vessels such as the aorta. Elastin is also very important in the lungs, ligaments, the skin, the bladder, and elastic cartilage. It is present in all vertebrates above the jawless fish.
In humans, elastin is encoded by the "ELN" gene.