Novel extracellular matrix-associated serine proteinase inhibitors from human skin fibroblasts.
Serine proteinase inhibitors play a major role in the turnover of connective tissues. In this study, we isolated and determined partial amino-terminal amino acid sequence of trypsin/elastase/plasmin inhibitors (M(r) 33,000 and 31,000) from the extracellular matrix of SV40-transformed human skin fibroblasts. The antitrypsin activity of the inhibitors was monitored by substrate reverse zymography. Polyclonal antisera to alpha 1-antitrypsin, alpha 1-antichymotrypsin, alpha 2-antiplasmin, inter-alpha-trypsin inhibitor, plasminogen activator inhibitors-1 and -2, and a monoclonal antibody to protease nexin-1 did not label the 33-, 31-, and 27-kDa inhibitors. A computer search for amino acid sequence homology indicated that the 31-kDa inhibitor is novel. In contrast, the sequence of the 33-kDa inhibitor shared 70 to 90% homology with the amino-terminal sequence of a recently characterized 32-kDa trypsin/tissue factor inhibitor called tissue factor pathway inhibitor-2. The 33- and 31-kDa inhibitors bind to heparin-Sepharose and were recovered from the affinity beads as well as from the t12 FB extracellular matrix with 1 M NaCl. Based on these results, we propose that the extracellular matrix of human mesenchymal cells sequester a family of novel serine proteinase inhibitors.
Rao
C N
CN
Department of Dermatology, Northwestern University Medical School, Northwestern University, Chicago, Illinois 60611.
Liu
Y Y
YY
Peavey
C L
CL
Woodley
D T
DT
D000595:Amino Acid Sequence; D002461:Cell Line, Transformed; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D015842:Serine Proteinase Inhibitors / Q000302:isolation & purification*; D012867:Skin / Q000378:metabolism*
D015842:Serine Proteinase Inhibitors