The expanded collagen VI family: new chains and new questions

Abstract

Collagen VI is a component of the extracellular matrix of almost all connective tissues, including cartilage, bone, tendon, muscles and cornea, where it forms abundant and structurally unique microfibrils organized into different suprastructural assemblies. The precise role of collagen VI is not clearly defined although it is most abundant in the interstitial matrix of tissues and often found in close association with basement membranes. Three genetically distinct collagen VI chains, α1(VI), α2(VI) and α3(VI), encoded by the COL6A1, COL6A2 and COL6A3 genes, were first described more than 20 years ago. Their molecular assembly and role in congenital muscular dystrophy has been broadly characterized. In 2008, three additional collagen VI genes arrayed in tandem at a single gene locus on chromosome 3q in humans, and chromosome 9 in mice, were described. Following the naming scheme for collagens the new genes were designated COL6A4, COL6A5 and COL6A6 encoding the α4(VI), α5(VI) and α6(VI) chains, respectively. This review will focus on the current state of knowledge of the three new chains.

Variants of genes encoding collagens and matrix metalloproteinase system increased the risk of aortic dissection

“…Previous study associated collagen type VI with Bethlem myopathy (Fitzgerald et al, 2013). However, our LOF variants affected AD patients did not have related symptoms or family history after carefully physical examination and inquiry.…”

Skin Protective Effects of Nannochloropsis gaditana Extract on H2O2-Stressed Human Dermal Fibroblasts

“…Collagen production also contributes to skin hydration as well as to skin aging. Collagens are extracellular matrix proteins and have a triplehelical domain as their common structural element, that play a key role in maintaining the integrity of various tissues (Fitzgerald et al, 2013). Transcripts of Col6A1 were found to be upregulated in all cells pretreated with NannoG in contrast to stressed cells, a response very similar to that observed for AQP3 transcripts.…”

“…Transcripts of Col6A1 were found to be upregulated in all cells pretreated with NannoG in contrast to stressed cells, a response very similar to that observed for AQP3 transcripts. Although there are limited studies focused on the action of Col6A1 in primary fibroblasts (Gruber and Holtz, 2010;Fitzgerald et al, 2013), some evidence supports its woundhealing role as a Col6A1 null mice do not display an overt wound healing process (Lettmann et al, 2014). Transcripts of fibrillin-1 (FBN1) also showed significant changes under our experimental conditions.…”

Ageing of the vitreous: From acute onset floaters and flashes to retinal detachment

“…Type VI collagen is a minor representative of collagens in the human vitreous that binds to fibrillar collagens and HA and forms a stabilizing fine filamentous vitreous network (Marshall, 1987;Fitzgerald et al, 2013). Each of the three different chains of the protein contains a short triple-helical domain, and the remainder consists of large N-and C-terminal globular domains (Prockop and Kivirikko, 1995).…”