• Purity

  >90%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie? Blue Staining.

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to induce adhesion of ATDC5 mouse chondrogenic cells. The ED    ₅₀ for this effect is 0.15-0.9 μg/mL.    
   

• Source

  Mouse myeloma cell line, NS0-derived Gln20-Val755, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  No results obtained. Gln20 inferred from enzymatic pyroglutamate treatment revealing Gly21    
   

• Structure / Form

  Disulfide-linked pentamer    
   

• Predicted Molecular Mass

  81 kDa

• SDS-PAGE

  85-115 kDa, reducing conditions    
   

Data Images

Background: COMP/Thrombospondin-5

Cartilage Oligomeric Matrix Protein (COMP), also known as Thrombospondin-5, is a 110 kDa multidomain calcium binding protein that associates with other extracellular matrix molecules. Thrombospondin-1 and -2 constitute subgroup A and form homotrimers, whereas Thrombospondin-3, -4, and COMP constitute subgroup B and form homopentamers (1-4). Mouse COMP contains a non-collagenous coiled-coil domain, four EGF-like repeats, eight TSP type-3 repeats, and a globular TSP C-terminal domain (5). It shares 92% and 98% aa sequence identity with human and rat COMP, respectively. The coiled coil domain mediates the association of COMP into disulfide-linked homopentamers with a central hub and peripheral globular domains connected by flexible strands (6, 7). An axial pore is formed by the coiled coil assembly and binds vitamin D  ₃ which is involved in bone and cartilage metabolism (8). An RGD sequence in the third TSP type-3 repeat mediates chondrocyte attachment   via Integrin  alpha 5 beta 1, although when reduced and in the absence of calcium, attachment is mediated   via Integrin  alpha V beta 3 (9). COMP is up-regulated in rheumatoid arthritis and osteoarthritis, hepatocellular carcinomas, chronic pancreatitis, and pancreatic carcinomas (10-12). Elevated circulating COMP levels are used as a biomarker for early onset of some skeletal disorders (10). Several mutations are associated with skeletal dysplasias, and the most common, a point mutation in the third TSP type-3 repeat, results in diminished calcium binding ability (13, 14).

• References:

1. Adams, J.C. and J. Lawler (2004) Int J. Biochem. Cell Biol. 36:961.

2. Posey, K.L. et al. (2014) Matrix Biol. 37:167.

3. Adams, J.C. (2004) Int. J. Biochem. Cell Biol. 36:1102.

4. Mann, H.H. et al. (2004) J. Biol. Chem. 279:25294.

5. Fang, C. et al. (2000) J. Orthop. Res. 18:593.

6. DiCesare, P. et al. (1995) J. Orthopaedic Res. 13:422.

7. Efimov, V.P. et al. (1994) FEBS Lett. 341:54.

8. Ozbek, S., et al. (2002) EMBO J. 21:5960.

9. Chen, F.H., et al. (2005) J. Biol. Chem. 280:32655.

10. Wislowska, M. and B. Jablonska (2005) Clin. Rheumatol. 24:278.

11. Xiao, Y. et al. (2004) J. Gastroenterol. Hepatol. 19:296.

12. Liao, Q. et al. (2003) Scand. J. Gastroenterol. 38:207.

13. Kennedy, J., et al. (2005) Eur. J. Hum. Genet. 13:547.

14. Hou, J. et al. (2000) Cell Calcium 27:309.

• Long Name:

  Cartilage Oligomeric Matrix Protein

• Entrez Gene IDs:

  1311 (Human); 12845 (Mouse)

• Alternate Names:

  cartilage oligomeric matrix protein (pseudoachondroplasia, epiphyseal dysplasia1, multiple); cartilage oligomeric matrix protein; cartilage oligomeric matrix protein(pseudoachondroplasia, epiphyseal dysplasia1, multiple); COMP; EDM1; EPD1; MED; MEDMGC131819; MGC149768; PSACH; pseudoachondroplasia (epiphyseal dysplasia 1, multiple); THBS5; Thrombospondin5; Thrombospondin-5; TSP5