Fibrillin 1

Protein encoded by the FBN1 gene

Fibrillin-1 is a glycoprotein that is essential for the formation of elastic fibers found in connective tissue. It is encoded by the FBN1 gene in humans. Fibrillin-1 is a major component of the extracellular matrix and plays a critical role in maintaining the structural integrity and function of various tissues.

Structure

Fibrillin-1 is a large glycoprotein with a molecular weight of approximately 350 kDa. It is composed of multiple epidermal growth factor-like (EGF-like) domains, which are interspersed with transforming growth factor beta (TGF-β) binding protein-like domains. These domains are crucial for the protein's ability to interact with other components of the extracellular matrix and to bind calcium, which is necessary for its structural stability.

Function

Fibrillin-1 is a key structural component of microfibrils, which are 10-12 nm diameter fibrils that provide a scaffold for the deposition of elastin in elastic fibers. These fibers are essential for the elasticity and resilience of tissues such as the skin, lungs, and blood vessels. Fibrillin-1 also plays a role in regulating the bioavailability of TGF-β, a cytokine involved in cell growth and differentiation.

Genetics

The FBN1 gene is located on chromosome 15 (15q21.1) and consists of 65 exons. Mutations in this gene can lead to a variety of connective tissue disorders, most notably Marfan syndrome. These mutations can result in the production of abnormal fibrillin-1 protein, which disrupts the formation and function of microfibrils.

Clinical significance

Mutations in the FBN1 gene are associated with several disorders:

• Marfan syndrome: A connective tissue disorder characterized by tall stature, long limbs, and cardiovascular abnormalities such as aortic aneurysm and mitral valve prolapse.
• Ectopia lentis: Dislocation of the lens of the eye, which can occur in isolation or as part of Marfan syndrome.
• Weill-Marchesani syndrome: A rare disorder characterized by short stature, brachydactyly, and lens dislocation.

Research and developments

Research into fibrillin-1 continues to provide insights into the pathogenesis of connective tissue disorders and potential therapeutic approaches. Understanding the molecular mechanisms by which fibrillin-1 mutations lead to disease can inform the development of targeted treatments.

Related pages

• Connective tissue
• Elastic fiber
• Extracellular matrix
• Marfan syndrome
• Ectopia lentis