Collagen- Family of fibrous proteins, 20+ genetically distinct types identified; provides structural stability and accounts for 70–80% dry weight of dermis; major dermal constituent
- Composed of three chains combined into a triple helix configuration; contains Gly-x-y repeats (glycine always third residue, x frequently proline, y often hydroxylysine or hydroxyproline)
- Collagen degraded by interstitial collagenases (metalloproteinases or MMPs)
- Collagen synthesis stimulated by retinoic acid
- Collagen synthesis inhibited by: IL-1 (↑ MMP expression), glucocorticoids, IFNγ, TNFα, D-penicillamine, UV irradiation
| | | | | | | Table 1-5 Types of Collagen | | Collagen | | Location | | Associated Diseases | | I | | Dermis, bone, ligament/tendon | | Ehers-Danlos syndrome, arthrochalasia (EDS type VII), osteogenesis imperfecta | | II | | Vitreous humor, cartilage | | | | III | | Fetal skin, blood vessels | | EDS vascular (type IV) | | IV | | Basement membrane | | Alport and Goodpasture syndrome | | V | | Ubiquitous | | EDS classic (type I/II) | | VI | | Aorta, placenta | | Congenital muscular dystrophy | | VII | | Anchoring fibrils (BMZ) | | Dystrophic EB (DEB) | | VIII | | Cornea (Descemet’s membrane: basement membrane between corneal proper substance and endothelial layer) | | Corneal dystrophy | | IX-XII | | Cartilage | | - | | XV–XVI | | Placenta | | - | | XVII (BPAG2) | | Hemidesmosome | | Junctional EB (JEB) | | | | | | | |
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