Collagen type XIV is a member of the fibril-associated collagens with interrupted triple helices (FACIT) family, expressed in most mesenchymal tissues. The non-collagenous domain at the N-terminus of collagen XIV is extremely large, nearly 80% of the entire polypeptide. This domain is composed of eight fibronectin type III repeats, two von Willebrand factor A-like (vWFA) domains and one non-collagenous domain 4 (NC4 domain) related to collagen type IX. Collagen XIV is expressed in most mesenchymal tissues where it appears to interact with collagen type VI, glycosaminoglycans, proteoglycans and matrix receptors (Brown et al. 1993, Imhof & Trueb 1998). It has been implicated as a regulator of fibrillogenesis. Collagen type XIV deficient mice have a grossly normal phenotype but their skin has altered mechanical properties. Tendons were seen to be enlarged at postnatal day 4 though mature tendons appeared normal. Tendons from postnatal day 7 KO mice had reduced strength but by 60 days were comparable with wild-type (Ansorge et al. 2009). Adult Col14a1 mice have defects in ventricular morphogenesis (Tao et al. 2012).
Collagen type XIV is degraded by MMP9 (Sires et al. 1995) and MMP13 (Knauper et al. 1997).