TYROSINE-RICH ACIDIC MATRIX PROTEIN (TRAMP) IS A TYROSINE-SULFATED AND WIDELY DISTRIBUTED PROTEIN OF THE EXTRACELLULAR-MATRIX

Tyrosine-rich acidic matrix protein (TRAMP; 22 kDa extracellular matrix protein; dermalopontin) is a protein that co-purifies with lysyl oxidase and with dermatan sulphate proteoglycans, with possible functions in cell-matrix interactions and matrix assembly. Using a rabbit polyclonal antiserum raised against porcine TRAMP, which cross-reacts with both the human and murine forms of the protein, we show by immunoblotting that TRAMP has a widespread tissue distribution, including skin, skeletal muscle, heart, lung, kidney, cartilage and bone. In cultures of human skin fibroblasts, TRAMP incorporates both [S-35]sulphate and [H-3]tyrosine and is secreted into the medium, as shown by immunoprecipitation. Amino acid analysis of immunoprecipitated TRAMP demonstrates that many of the tyrosine residues in TRAMP are sulphated.