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elastin; tropoelastin (ELN)

Function: - elastic protein in connective tissue - allows many tissues in the body to resume their shape after stretching or contracting - helps skin to return to its original position when displaced - role in load-bearing tissue where mechanical energy is stored (tendons) - forms a ternary complex with BGN & MFAP2 - interacts with MFAP2 via divalent cations (Ca+2 > Mg+2 > Mn+2) dose-dependent & saturatable Structure: - primarily composed of Gly, Val, Ala, & Pro - made by linking many soluble tropoelastins, in a reaction catalyzed by lysyl oxidase, to make a massive insoluble, durable cross-linked array - cross-linking is via Lys - most abundant cross-links in mature elastin fibers are lysinonorleucine, allysine aldol, desmosine, & isodesmosine - desmosine is a variant amino acid residue unique to elastin - hydroxylation on proline residues within the sequence motif, GXPG Compartment: extracellular matrix Alternative splicing: named isoforms=13 Expression: - produced by fibroblasts via cross-linking of soluble tropoelastin - arteries, especially large elastic blood vessels (aorta) - lungs, elastic ligaments, dermis of skin, bladder, & elastic cartilage - 1/2 life of elastin > 70 years [6] Pathology: - defects in ELN are the cause of a) cutis laxa, autosomal dominant, type 1 b) supravalvular aortic stenosis - haploinsufficiency of ELN may be the cause of certain cardiovascular & musculoskeletal abnormalities observed in Williams-Beuren syndrome - loss of elastin fibers* & an increase in cross-linking leads to remodeling of the lung elastin-collagen network contributing to chest wall stiffness & decreases in peak expiratory flow in the elderly - loss of elastin fibers* in the dermis of the skin [5], decreased skin elasticity [4] - at least 5 matrix metalloproteinases can degrade elastin & precursor tropoelastin, MMP-2, MMP-7, MMP-9, MMP-12 & MMP-14 [7] - elastin degradation products (bioactive elastin peptides) are suggested to play a role in progression of cardiovascular diseases that accompany elastin breakdown [7] * loss of elastin fibers hypothesized to occur via decrease in fibrolasts that produce elastin Genetics: - the elastin gene is located in the Williams-Beuren syndrome critical region Laboratory: - elastin, collagen & total protein in tissue

Related

desmosine elastase elastin receptor (ELNR1)

Specific

tropoelastin

General

matric protein; extracelluar matrix protein

Properties

SIZE: entity length = 786 aa MW = 68 kD COMPARTMENT: extracellular matrix MOTIF: signal sequence {1-26} alanine-rich region {97-102} MOTIF: alanine residue (SEVERAL) alanine-rich region {236-742} MOTIF: alanine residue (SEVERAL) cysteine residue {C776} MODIFICATION: cysteine residue {C781} cysteine residue {C781} MODIFICATION: cysteine residue {C776}

Database Correlations

OMIM correlations UniProt P15502 Entrez Gene 2006 Kegg hsa:2006

References

  1. Wikipedia - elastin entry http://en.wikipedia.org/wiki/Elastin
  2. UniProt :accession P15502
  3. GeneReviews http://www.ncbi.nlm.nih.gov/sites/genetests/lab/gene/ELN
  4. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  5. Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013 - Geriatric Review Syllabus, 11th edition (GRS11) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2022
  6. Heinz A Elastases and elastokines: elastin degradation and its significance in health and disease. Crit Rev Biochem Mol Biol. 2020 Jun;55(3):252-273. PMID: 32530323 Review.
  7. Miekus N, Luise C, Sippl W, Baczek T, Schmelzer CEH, Heinz A. MMP-14 degrades tropoelastin and elastin. Biochimie. 2019 Oct;165:32-39. PMID: 31278967
  8. Baumann L, Bernstein EF, Weiss AS et al Clinical Relevance of Elastin in the Structure and Function of Skin. Aesthet Surg J Open Forum. 2021 May 14;3(3):ojab019. PMID: 34195612 PMCID: PMC8239663 Free PMC article.
  9. Wang K, Meng X, Guo Z. Elastin Structure, Synthesis, Regulatory Mechanism and Relationship With Cardiovascular Diseases. Front Cell Dev Biol. 2021 Nov 30;9:596702. PMID: 34917605 PMCID: PMC8670233 Free PMC article. Review.
  10. Trebacz H, Barzycka A. Mechanical Properties and Functions of Elastin: An Overview. Biomolecules. 2023 Mar 22;13(3):574. PMID: 36979509 PMCID: PMC10046833 Free PMC article. Review.