Type V collagen also helps to form cell surfaces and hair. NM_001851NM_078485NM_001377289NM_001377290NM_001377291, NP_001842NP_511040NP_001364218NP_001364219NP_001364220, Collagen alpha-1(IX) chain is a protein that in humans is encoded by the COL9A1 gene. The following flash movie demonstrates collagen synthesis to fibrils. Decorin, for example, was so named for its capacity to ‘decorate’ collagen fibers. Mutations in type IX collagen can predispose individuals to multiple epiphyseal dysplasia, a clinically highly heterogeneous skeletal disorder, with early-onset osteoarthritis as a very common manifestation. To investigate targets in OA pathogenesis, animal models of OA have allowed to further dissect the role of β-catenin in the synthesis of ECM and its degradation. Whereas the underlying cause of RP remains under investigation, a genetic predisposition to the development of autoimmunity against type II, IX, and XI collagens as well as martrilin-1 and proteoglycans appears to contribute to its pathophysiology (Michet, 2016). The NC3 domain has one chondroitin sulfate chain attachment site.279 The length of the chondroitin sulfate chain may vary depending on the tissue type and developmental stage. FACITs modulate the surface properties of the fibrillar collagens by incorporating in the interfibrillar space in staggered fibrils. Eighty percent to 90 percent of the collagen in the human body consists of types I, II, and III collagen, although at least 16 different forms of the protein are known. Collagen type XVI, XIX, XXI and XXII are grouped as FACIT-like collagens, because even though they share certain structural homologies to FACITs they have distinct functional properties. In vitreous, the type IX collagen is synthesized in a proteoglycan form, but the length and sulfation pattern of the chondroitin sulfate chain is species dependent. The short form of type IX collagen in chick embryo vitreous humor has a long chondroitin sulfate chain in the NC3 domain of the α2(IX) chain.280 The α1(IX) chain in bovine nucleus pulposus, the central zone of the intervertebral disc, has only a short form of the α1(IX) chain and lacks the NC4 domain, while the α1(IX) chain in hyaline cartilage has the long form of the α1(IX) chain.281, Type IX collagen molecules assemble with type II and XI collagens to form the fibrils in hyaline cartilage. 9 Health Benefits of Collagen. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B978012809847900009X, URL: https://www.sciencedirect.com/science/article/pii/B9780123742032002578, URL: https://www.sciencedirect.com/science/article/pii/B9780080453828006985, URL: https://www.sciencedirect.com/science/article/pii/B9780128012383622158, URL: https://www.sciencedirect.com/science/article/pii/B9780123944474200679, URL: https://www.sciencedirect.com/science/article/pii/B9780123971579000035, URL: https://www.sciencedirect.com/science/article/pii/B9780123813619000214, URL: https://www.sciencedirect.com/science/article/pii/B9780323316965000693, URL: https://www.sciencedirect.com/science/article/pii/B9780128012383110621, URL: https://www.sciencedirect.com/science/article/pii/B9780323316965000036, Biochemistry of Collagens, Laminins and Elastin, Molecular Composition of the Vitreous and Aging Changes, Hans Peter BächingerKazunori MizunoJanice A. VrankaSergei P. Boudko, in, Regulation of Cartilage Matrix Protein by Transcription Factors, SOX9 and β-Catenin, Stem Cell Biology and Tissue Engineering in Dental Sciences, Etiology and Pathogenesis of Rheumatoid Arthritis, Kelley and Firestein's Textbook of Rheumatology (Tenth Edition). Proteoglycans are considered a primary component facilitating the sequestration of signaling molecules in the ECM. Type II. A potential role of cathepsins as mediators of bone destruction in arthritis was confirmed in studies in which cysteine protease inhibitors significantly decrease joint damage in the rodent arthritis models.