Elastin
Proteins

Author: Alessandra S
Date: 17/02/2012

Description

DEFINITION

Elastin is a structural protein that provides elasticity in connective tissues. Elasticity is especially important for blood vessels and lung tissues, which have an expectedly high elastin content.

Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin , 2016

THE GENE

DatabaseLink
HGNCELN
UniprotELN_HUMAN

CHEMICAL STRUCTURE AND IMAGES

When relevant for the function

  • Primary structure
  • Secondary structure
  • Tertiary structure
  • Quaternary structure

Protein Aminoacids Percentage (Width 700 px)

SYNTHESIS AND TURNOVER

Downregulation

Ascorbate

Ascorbate Differentially Regulates Elastin and Collagen Biosynthesis in Vascular Smooth Muscle Cells and Skin Fibroblasts by Pretranslational Mechanisms 1997(19)78600-1/fulltext

  • Ascorbate contributes to several metabolic processes including efficient hydroxylation of hydroxyproline in elastin, collagen, and proteins with collagenous domains, yet hydroxyproline in elastin has no known function. Prolyl hydroxylation is essential for efficient collagen production; in contrast, ascorbate has been shown to decrease elastin accumulation in vitro and to alter morphology of elastic tissues in vivo. Ascorbate doses that maximally stimulated collagen production (10-200 μM) antagonized elastin biosynthesis in vascular smooth muscle cells and skin fibroblasts, depending on a combination of dose and exposure time. Diminished elastin production paralleled reduced elastin mRNA levels, while collagen I and III mRNAs levels increased. We compared the stability of mRNAs for elastin and collagen I with a constitutive gene after ascorbate supplementation or withdrawal. Ascorbate decreased elastin mRNA stability, while collagen I mRNA was stabilized to a much greater extent. Ascorbate withdrawal decreased collagen I mRNA stability markedly (4.9-fold), while elastin mRNA became more stable. Transcription of elastin was reduced 72% by ascorbate exposure. Differential effects of ascorbic acid on collagen I and elastin mRNA abundance result from the combined, marked stabilization of collagen mRNA, the lesser stability of elastin mRNA, and the significant repression of elastin gene transcription.
Smoke

smoke+and+elastin

UV

uv+and+skin+elastin

mRNA synthesis
protein synthesis

post-translational modifications
degradation

CELLULAR FUNCTIONS

cellular localization,

It is classed as a fibrous protein because of its structural function and relative insolubility in water. Elastin lacks a regular secondary structure. As in collagen, allysines form cross-links in elastin. An extracellular lysine amino oxidase converts lysine side chains in the sequence –Lys-Ala-Ala-Lys and –Lys-Ala-Ala-Ala-Lys to allysines. Three allysines and an unmodified lysine from different regions in the polypeptide chains react to form the heterocyclic structure of desmosine or isodesmosine, which cross-links the polypeptide chains in elastin networks.
The amino-acid composition of elastin is rich in proline and glycine, like that of collagen, but elastin does not have glycine as every third residue, nor does it have a triple-helical structure.
Instead, elastin is rich in alanine and valine.
A prototypical elastin sequence is Val–Pro–Gly–Val–Gly, and peptides composed of (Val–Pro–Gly–Val–Gly)n repeats are substrates for P4H.
The creation of Hyp in elastin is catalyzed by the collagen P4H, but there is less Hyp in elastin than in collagen and Hyp is not required for elastin biosynthesis or secretion

Proline in elastin-like polymers is efficiently hydroxylated under conditions where these polymers exhibit preferred secondary and tertiary structures.
biological function
h4 Elastin and Emilin 1, 2, 3

The EMILIN/multimerin family, 2011

  • Enzymes
DatabaseLink
BRENDA - The Comprehensive Enzyme Information SystemElastin
KEGG PathwaysElastin
Human Metabolome Databaseelastin

Elastin related enzymes AA

  • Cell signaling and Ligand transport
  • Structural proteins

REGULATION

DIAGNOSTIC AND THERAPEUTIC USES

Clinical Relevance of Elastin in the Structure and Function of Skin, 2021

  • Abstract
    Elastin is the main component of elastic fibers, which provide stretch, recoil, and elasticity to the skin. Normal levels of elastic fiber production, organization, and integration with other cutaneous extracellular matrix proteins, proteoglycans, and glycosaminoglycans are integral to maintaining healthy skin structure, function, and youthful appearance. Although elastin has very low turnover, its production decreases after individuals reach maturity and it is susceptible to damage from many factors. With advancing age and exposure to environmental insults, elastic fibers degrade. This degradation contributes to the loss of the skin’s structural integrity; combined with subcutaneous fat loss, this results in looser, sagging skin, causing undesirable changes in appearance. The most dramatic changes occur in chronically sun-exposed skin, which displays sharply altered amounts and arrangements of cutaneous elastic fibers, decreased fine elastic fibers in the superficial dermis connecting to the epidermis, and replacement of the normal collagen-rich superficial dermis with abnormal clumps of solar elastosis material. Disruption of elastic fiber networks also leads to undesirable characteristics in wound healing, and the worsening structure and appearance of scars and stretch marks. Identifying ways to replenish elastin and elastic fibers should improve the skin’s appearance, texture, resiliency, and wound-healing capabilities. However, few therapies are capable of repairing elastic fibers or substantially reorganizing the elastin/microfibril network. This review describes the clinical relevance of elastin in the context of the structure and function of healthy and aging skin, wound healing, and scars and introduces new approaches being developed to target elastin production and elastic fiber formation.

elastin covid-19

Comments
2012-02-17T21:57:54 - Alessandra S

REGULATION OF ELASTIN BIOSYNTESIS BY ASCORBIC ACID

The accumulation of elastin is affected by levels of ascorbic acid. Cell cultures grown in the presence of ascorbate produce over-hydroxylated elastin that is less cross-linked and more soluble.
Apparently, Hyp levels affect the formation of elastin fibrils. Ascorbate dramatically affects insoluble elastin synthesis, accumulation, and cross-link formation.
Cells grown in the presence of ascorbate synthesize and accumulate significantly less insoluble elastin than non-ascorbate cultures.
Those elastin molecules which do become incorporated into the extracellular matrix in the presence of ascorbate contain a slightly elevated content of hydroxyproline and lysine and, most importantly, are turned over more rapidly. The amount of hydroxyproline accumulated in the cell layers grown in the presence of ascorbate is 2.5 times that present in the absence of ascorbate.

Effects of ascorbate on insoluble elastin accumulation and cross-link formation, 1982

Much less elastin is accumulated in the extracellular matrix of the ascorbate-treated cultures than in the matrix of those cultures not treated with ascorbate. The insoluble elastin matrix produced in the presence of ascorbate contains a somewhat higher content of hydroxyproline and lysine and slightly less lysine-derived cross-links than the non-ascorbate cultures.

Those highly hydroxylated elastin molecules which become bound to the matrix in spite of the presence of ascorbate probably cannot assume an appropriate fiber orientation for cross-link formation and thus can be more easily solubilized by either nonspecific proteolysis.
In the ascorbate-treated cultures the majority of the elastin molecules incorporated into the cell layer during the pulse period are not processed into the insoluble matrix via the normal cross-linking events. Interestingly enough, the portion of elastin in the ascorbate-treated cultures which remains insoluble does have reasonable levels of cross-links. This suggests that some tropoelastin units may not be as extensively hydroxylated as others and thus are capable of being cross-linked.

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