Developmental Stage-dependent Regulation of Prolyl 3-Hydroxylation in Tendon Type I Collagen |
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Authors: | Yuki Taga Masashi Kusubata Kiyoko Ogawa-Goto Shunji Hattori |
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Institution: | From the Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017, Japan |
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Abstract: | 3-Hydroxyproline (3-Hyp), which is unique to collagen, is a fairly rare post-translational modification. Recent studies have suggested a function of prolyl 3-hydroxylation in fibril assembly and its relationships with certain disorders, including recessive osteogenesis imperfecta and high myopia. However, no direct evidence for the physiological and pathological roles of 3-Hyp has been presented. In this study, we first estimated the overall alterations in prolyl hydroxylation in collagens purified from skin, bone, and tail tendon of 0.5–18-month-old rats by LC-MS analysis with stable isotope-labeled collagen, which was recently developed as an internal standard for highly accurate collagen analyses. 3-Hyp was found to significantly increase in tendon collagen until 3 months after birth and then remain constant, whereas increased prolyl 3-hydroxylation was not observed in skin and bone collagen. Site-specific analysis further revealed that 3-Hyp was increased in tendon type I collagen in a specific sequence region, including a previously known modification site at Pro707 and newly identified sites at Pro716 and Pro719, at the early ages. The site-specific alterations in prolyl 3-hydroxylation with aging were also observed in bovine Achilles tendon. We postulate that significant increases in 3-Hyp at the consecutive modification sites are correlated with tissue development in tendon. The present findings suggest that prolyl 3-hydroxylation incrementally regulates collagen fibril diameter in tendon. |
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Keywords: | collagen development mass spectrometry (MS) post-translational modification (PTM) tendon 3-hydroxyproline |
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