DEGRADATION OF THE COL1 DOMAIN OF TYPE-XIV COLLAGEN BY 92-KDA GELATINASE

Type XIV collagen is a newly described member of the fibril-associated collagens with interrupted triple helices (FACITs). Expression of thi s collagen has been localized to various embryonic tissues, suggesting that it has a functional role in development. All FACITs thus far des cribed (types IX, XII, XIV, and XVI) contain a highly homologous carbo xyl-terminal triple helical domain designated COL1. We have studied th e capacity of various matrix metalloproteinases (interstitial collagen ase, stromelysin, matrilysin, and 92-kDa gelatinase) to degrade the CO L1 domain of collagen XIV. We found that only 92-kDa gelatinase cleave s COL1. Furthermore, digestion of whole native collagen XIV by the 92- kDa gelatinase indicates that this enzyme specifically region of the m olecule. COL1 is cleaved by 92-kDa gelatinase at 30 degrees C, a full 5-6 degrees C below the melting temperature (T-m) of this domain; nati ve collagen XIV is also degraded at 30 degrees C. In comparison to int erstitial collagenase degradation of its physiologic native type I col lagen substrate, the 92-kDa enzyme cleaved COL1 (XIV) with comparable catalytic efficacy. Interestingly, following thermal denaturation of t he COL1 fragment, its susceptibility to 92-kDa gelatinase increases, b ut only to a degree that leaves it several orders of magnitude less se nsitive to degradation than denatured collagens I and III. These data indicate that native COL1 and collagen XIV are readily and specificall y cleaved by 92-kDa gelatinase. They also suggest a role for 92-kDa ge latinase activity in the structural tissue remodeling of the developin g embryo.