Tendon extracellular matrix contains pentameric thrombospondin-4 (TSP-4).
In preparations of cartilage oligomeric matrix protein (COMP) from bovine tendon two contaminating polypeptides of 120 and 135 kDa were detected. N-terminal protein sequencing of these polypeptides showed homology to the N-terminus and to an internal sequence in TSP-4, respectively. TSP-4 was further enriched by heparin affinity chromatography. Electron microscopy of this sample shows primarily five armed particles with globular domains at the periphery connected to a central assembly domain in which smaller N-terminal globular domains can be resolved tightly packed at the center of the particle. We can thereby confirm the pentameric model for TSP-4 proposed by Lawler et al. [(1995) J. Biol. Chem. 270, 2809-2814], on the basis of recombinantly expressed protein. We further show that TSP-4 is abundant in tendon.
Hauser
N
N
Institute for Biochemistry, Medical Faculty, University of Cologne, Germany.
Paulsson
M
M
Kale
A A
AA
DiCesare
P E
PE
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid; D005109:Extracellular Matrix / Q000737:chemistry*; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification* / Q000648:ultrastructure; D006493:Heparin / Q000378:metabolism; D064235:Matrilin Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017434:Protein Structure, Tertiary; D017421:Sequence Analysis; D013710:Tendons / Q000737:chemistry*; D019699:Thrombospondins
D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; D019699:Thrombospondins; D006493:Heparin