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Elastin

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Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of vertebrates and used in places where mechanical energy is required to be stored. In humans, elastin is encoded by the ELN gene.[1]

Function

The ELN gene encdes a protein that is one of the two components of elastic fibers. The encoded protein is rich in hydrophobic amino acids such as glycine and proline, which form mobile hydrophobic regions bounded by crosslinks between lysine residues.[2] Multiple transcript variants encoding different isoforms have been found for this gene.[2] The other name for elastin is tropoelastin.[3] The characterization of disorder is consistent with an entropy-driven mechanism of elastic recoil. It is concluded that conformational disorder is a constitutive feature of elastin structure and function.[4]

Clinical significance

Deletions and mutations in this gene are associated with supravalvular aortic stenosis (SVAS) and autosomal dominant cutis laxa.[2] Other associated defects in elastin include Marfan's Syndrome and emphysema caused by α1-antitrypsin deficiency.

Composition

Elastic fiber is composed of the protein fibrillin and elastin made of simple amino acids such as glycine, valine, alanine, and proline.[5] The total elastin ranges from 58 to 75% of the weight of the dry defatted artery in normal canine arteries.[6] Comparison between fresh and digested tissues shows that, at 35% strain, a minimum of 48% of the arterial load is carried by elastin, and a minimum of 43% of the change in stiffness of arterial tissue is due to the change in elastin stiffness.[7] Elastin is made by linking many soluble tropoelastin protein molecules, in a reaction catalyzed by lysyl oxidase, to make a massive insoluble, durable cross-linked array. The amino acid responsible for these cross-links is lysine.( requiring vitamin C- see vitamin C foundation) Tropoelastin is a specialized protein with a molecular weight of 64 to 66 kDa, and an irregular or random coil conformation made up of 830 amino acids.

Desmosine and isodesmosine are types of links for the tropoelastin molecules.

Tissue distribution

Elastin serves an important function in arteries as a medium for pressure wave propagation to help blood flow and is particularly abundant in large elastic blood vessels such as the aorta. Elastin is also very important in the lungs, elastic ligaments, the skin, and the bladder, elastic cartilage. It is present in all vertebrates above the jawless fish.[8]

See also

References

  1. ^ Curran ME, Atkinson DL, Ewart AK, Morris CA, Leppert MF, Keating MT (April 1993). "The elastin gene is disrupted by a translocation associated with supravalvular aortic stenosis". Cell. 73 (1): 159–68. doi:10.1016/0092-8674(93)90168-P. PMID 8096434.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ a b c "Entrez Gene: elastin".
  3. ^ "Elastin (ELN)". Retrieved 31 October 2011.
  4. ^ Lisa D Muiznieks, Anthony S Weiss and Fred W Keeley (2010). "Structural disorder and dynamics of elastin". Biochem Cell Biol. 88 (2): 239–50. doi:10.1139/o09-161. PMID 20453927. {{cite journal}}: Cite has empty unknown parameter: |1= (help)
  5. ^ Kielty CM, Sherratt MJ, Shuttleworth CA (July 2002). "Elastic fibres". J. Cell. Sci. 115 (Pt 14): 2817–28. PMID 12082143.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ Grace M. Fischer M.D. Josep G. Llaurado M.D. (October 1966). "Collagen and Elastin Content in Canine Arteries Selected from Functionally Different Vascular Beds". Circulation Research. 19 (2): 394–399. doi:10.1161/01.res.19.2.394. PMID 5914851.
  7. ^ Lammers SR, Kao PH, Qi HJ, Hunter K, Lanning C, Albietz J, Hofmeister S, Mecham R, Stenmark KR, Shandas R. (July 2008). "Changes in the structure-function relationship of elastin and its impact on the proximal pulmonary arterial mechanics of hypertensive calves". Am J Physiol Heart Circ Physiol. 295 (4): H1451-9. doi:10.1152/ajpheart.00127.2008. PMC 2593497. PMID 18660454.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Sage EH, Gray WR (1977). "Evolution of elastin structure". Adv. Exp. Med. Biol. 79: 291–312. PMID 868643.

Further reading

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

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