THE C-TERMINAL DOMAIN OF TISSUE INHIBITOR OF METALLOPROTEINASES-2 IS REQUIRED FOR CELL-BINDING BUT NOT FOR ANTIMETALLOPROTEINASE ACTIVITY

We have generated a C-terminally-truncated form of recombinant tissue inhibitor of metalloproteinases-2 (designated rTIMP-2 delta) in which the region of the inhibitor extending from residue 128 to 194 and incl uding 3 of the 6 disulfide bonds is deleted. rTIMP-2 and rTIMP-2 delta had similar inhibitory activities toward interstitial collagenase and inhibited the activation of the precursor form of matrix metalloprote inase-2 (proMMP-2). rTIMP-2 also bound with high affinity (Kd 0.99 nM) to HT1080 human fibrosarcoma cells treated with 12-O-tetradecanoyl-ph orbol-13-acetate. However deletion of the C-terminal domain of TIMP-2 significantly lowered the cell surface binding affinity, with competit ion experiments indicating a 2 order of magnitude difference between r TIMP-2 and rTIMP-2 delta in the concentrations needed to displace I-12 5-labeled rTIMP-2 binding. These data indicate that the C-terminal dom ain of TIMP-2 is not required for the antimetalloproteinase activity b ut plays a major role in the high affinity cell surface binding of the inhibitor. (C) 1997 Academic Press.