INTERACTION OF MATRIX METALLOPROTEINASE-2 AND METALLOPROTEINASE-9 WITH PREGNANCY ZONE PROTEIN AND ALPHA(2)-MACROGLOBULIN

The binding of matrix metalloproteinases-2 and -9 to pregnancy zone pr otein and alpha(2)-macroglobulin was studied. The binding was demonstr ated by formation of dimeric as well as tetrameric complexes of pregna ncy zone protein and by the formation of alpha(2)-macroglobulin comple xes with fast and intermediate mobility in native gel electrophoresis. The complex formation was confirmed by the use of I-125-labeled matri x metalloproteinase-2. The cleavage sites in the ''bait'' regions foll owing formation of high-molecular-weight complexes of matrix metallopr oteinases with the alpha-macroglobulins were determined by protein seq uence analysis. Pregnancy zone protein was cleaved at Thr(693)-Tyr(694 ) and alpha(2)-macroglobulin at Gly(679)-Leu(680) and Arg(696)-Leu(697 ) by matrix metalloproteinase-2. Matrix metalloproteinase-9 cleaved al pha(2)-macroglobulin at the same site as matrix metalloproteinase-2, b ut cleavage of pregnancy zone protein was at Leu(753)-Ser(754). The se quences of the bands, visualized in the SDS gel, of approximately 90 a nd 165 kDa or higher molecular weight complexes were the same. This in dicates that the matrix metalloproteinases cleaved the inhibitors with or without binding to them. The present results suggest that matrix m etalloproteinases-2 and -9 may interact with pregnancy zone protein an d alpha(2)-macroglobulin in vivo. (C) 1997 Academic Press.