Cartilage associated protein explained

Cartilage associated protein is a protein that in humans is encoded by the CRTAP gene.^{[1] [2]}

Structure and function

The protein encoded by this gene is similar to the chicken and mouse CRTAP genes. The encoded protein is a scaffolding protein that may influence the activity of at least one member of the cytohesin/ARNO family in response to specific cellular stimuli.^[1]

CRTAP forms a tight protein complex with two other enzymes involved in post-translational modification: Leprecan (P3H1) and PPIB.^[3] In this complex, CRTAP acts as a collagen-binding site, capturing substrates for subsequent enzymatic processing by P3H1 and PPIB. Notably, CRTAP exhibits a folding pattern similar to the N-terminal domain of P3H1.

Clinical significance

Mutations in the CRTAP gene are associated with osteogenesis imperfecta, types VII and IIB, a connective tissue disorder characterized by bone fragility and low bone mass.^{[4] [5]}

Further reading

• Marini JC, Cabral WA, Barnes AM . Null mutations in LEPRE1 and CRTAP cause severe recessive osteogenesis imperfecta . Cell and Tissue Research . 339 . 1 . 59–70 . January 2010 . 19862557 . 3156555 . 10.1007/s00441-009-0872-0 .
• Morello R, Bertin TK, Chen Y, Hicks J, Tonachini L, Monticone M, Castagnola P, Rauch F, Glorieux FH, Vranka J, Bächinger HP, Pace JM, Schwarze U, Byers PH, Weis M, Fernandes RJ, Eyre DR, Yao Z, Boyce BF, Lee B . CRTAP is required for prolyl 3- hydroxylation and mutations cause recessive osteogenesis imperfecta . Cell . 127 . 2 . 291–304 . October 2006 . 17055431 . 10.1016/j.cell.2006.08.039 . 8123837 . free .
• Chang W, Barnes AM, Cabral WA, Bodurtha JN, Marini JC . Prolyl 3-hydroxylase 1 and CRTAP are mutually stabilizing in the endoplasmic reticulum collagen prolyl 3-hydroxylation complex . Human Molecular Genetics . 19 . 2 . 223–234 . January 2010 . 19846465 . 2796888 . 10.1093/hmg/ddp481 .
• Li GH, Kung AW, Huang QY . Common variants in FLNB/CRTAP, not ARHGEF3 at 3p, are associated with osteoporosis in southern Chinese women . Osteoporosis International . 21 . 6 . 1009–1020 . June 2010 . 19727905 . 2946578 . 10.1007/s00198-009-1043-6 .
• Bodian DL, Chan TF, Poon A, Schwarze U, Yang K, Byers PH, Kwok PY, Klein TE . Mutation and polymorphism spectrum in osteogenesis imperfecta type II: implications for genotype-phenotype relationships . Human Molecular Genetics . 18 . 3 . 463–471 . February 2009 . 18996919 . 2638801 . 10.1093/hmg/ddn374 .
• Morello R, Tonachini L, Monticone M, Viggiano L, Rocchi M, Cancedda R, Castagnola P . cDNA cloning, characterization and chromosome mapping of Crtap encoding the mouse cartilage associated protein . Matrix Biology . 18 . 3 . 319–324 . June 1999 . 10429950 . 10.1016/S0945-053X(99)00002-5 .
• Kimura K, Wakamatsu A, Suzuki Y, Ota T, Nishikawa T, Yamashita R, Yamamoto J, Sekine M, Tsuritani K, Wakaguri H, Ishii S, Sugiyama T, Saito K, Isono Y, Irie R, Kushida N, Yoneyama T, Otsuka R, Kanda K, Yokoi T, Kondo H, Wagatsuma M, Murakawa K, Ishida S, Ishibashi T, Takahashi-Fujii A, Tanase T, Nagai K, Kikuchi H, Nakai K, Isogai T, Sugano S . Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes . Genome Research . 16 . 1 . 55–65 . January 2006 . 16344560 . 1356129 . 10.1101/gr.4039406 .
• Castagnola P, Gennari M, Morello R, Tonachini L, Marin O, Gaggero A, Cancedda R . Cartilage associated protein (CASP) is a novel developmentally regulated chick embryo protein . Journal of Cell Science . 110 . 12 . 1351–1359 . June 1997 . 9217321 . 10.1242/jcs.110.12.1351 . 110 .
• Sowa ME, Bennett EJ, Gygi SP, Harper JW . Defining the human deubiquitinating enzyme interaction landscape . Cell . 138 . 2 . 389–403 . July 2009 . 19615732 . 2716422 . 10.1016/j.cell.2009.04.042 .
• Van Dijk FS, Nesbitt IM, Nikkels PG, Dalton A, Bongers EM, van de Kamp JM, Hilhorst-Hofstee Y, Den Hollander NS, Lachmeijer AM, Marcelis CL, Tan-Sindhunata GM, van Rijn RR, Meijers-Heijboer H, Cobben JM, Pals G . CRTAP mutations in lethal and severe osteogenesis imperfecta: the importance of combining biochemical and molecular genetic analysis . European Journal of Human Genetics . 17 . 12 . 1560–1569 . December 2009 . 19550437 . 2987020 . 10.1038/ejhg.2009.75 .

Notes and References

1. Web site: Entrez Gene: cartilage associated protein.
2. Tonachini L, Morello R, Monticone M, Skaug J, Scherer SW, Cancedda R, Castagnola P . cDNA cloning, characterization and chromosome mapping of the gene encoding human cartilage associated protein (CRTAP) . Cytogenetics and Cell Genetics . 87 . 3-4 . 191–194 . 1999 . 10702664 . 10.1159/000015463 . 24887051 .
3. Li W, Peng J, Yao D, Rao B, Xia Y, Wang Q, Li S, Cao M, Shen Y, Ma P, Liao R, Qin A, Zhao J, Cao Y . The structural basis for the collagen processing by human P3H1/CRTAP/PPIB ternary complex . Nature Communications . 15 . 1 . 7844 . September 2024 . 39245686 . 11381544 . 10.1038/s41467-024-52321-6 .
4. Barnes AM, Chang W, Morello R, Cabral WA, Weis M, Eyre DR, Leikin S, Makareeva E, Kuznetsova N, Uveges TE, Ashok A, Flor AW, Mulvihill JJ, Wilson PL, Sundaram UT, Lee B, Marini JC . Deficiency of cartilage-associated protein in recessive lethal osteogenesis imperfecta . The New England Journal of Medicine . 355 . 26 . 2757–2764 . December 2006 . 17192541 . 7509984 . 10.1056/NEJMoa063804 .
5. Baldridge D, Schwarze U, Morello R, Lennington J, Bertin TK, Pace JM, Pepin MG, Weis M, Eyre DR, Walsh J, Lambert D, Green A, Robinson H, Michelson M, Houge G, Lindman C, Martin J, Ward J, Lemyre E, Mitchell JJ, Krakow D, Rimoin DL, Cohn DH, Byers PH, Lee B . CRTAP and LEPRE1 mutations in recessive osteogenesis imperfecta . Human Mutation . 29 . 12 . 1435–1442 . December 2008 . 18566967 . 2671575 . 10.1002/humu.20799 .