Type V collagen is a fibril-forming collagen forming a group with collagen types I, II, III and XI (Gelse et al. 2003). Three different alpha chains exist that can combine in three distinct trimers. Collagen V forms fibrils that are associated with type I and to a lesser extent III collagen, as a minor but critical component of bone matrix, corneal stroma and the interstitial matrix of muscle, liver, lung and placenta (Birk et al. 1988). COL5A1-/- mice have an almost complete lack of collagen fibrils reflecting a central role in fibrillogenesis (Wenstrup et al. 2004). Type V collagen mutation results in a range of connective tissue diseases including Ehlers-Danlos syndrome (EDS), which is a heterogeneous group of disorders characterized by joint hypermobility and skin hyperextensibility, thinness and fragility. These result from mutations in the COL5A1 and COL5A2 genes (Michalickova et al. 1998, Schwarze et al. 2000).
Type V collagen is digested by MMP2 (Murphy et al. 1981, Veidal et al. 2011), MMP10 (Nicholson et al. 1989), and MMP9 (Murphy et al. 1982, Watanabe et al. 1993, Pourmotabbed et al. 1994, Niyibizi et al. 1994, Veidal et al. 2011).