tailieunhanh - Báo cáo khoa học: Calcium-induced activation and truncation of promatrix metalloproteinase-9 linked to the core protein of chondroitin sulfate proteoglycans

In the leukemic macrophage cell-line THP-1, a fraction of the secreted matrix metalloproteinase 9 (MMP-9) is linked to the core protein of chondroitin sulfate proteoglycans (CSPG). Unlike the monomeric and homodimeric forms of MMP-9, the addition of exogenous CaCl2 to the proMMP-9/CSPG complex resulted in an active gelatinase due to the induction of an autocatalytic removal of the N-terminal prodomain. In addition, the MMP-9 was released from the CSPG through a process that appeared to be a stepwise truncation of both the CSPG core protein and a part of the C-terminal domain of the gelatinase. . | Eur. J. Biochem. 270 3996-4007 2003 FEBS 2003 doi Calcium-induced activation and truncation of promatrix metalloproteinase-9 linked to the core protein of chondroitin sulfate proteoglycans Jan-Olof Winberg1 Eli Berg1 Svein O. Kolset2 and Lars Uhlin-Hansen1 1 Department of Biochemistry Institute of Medical Biology University of Troms0 Norway 2Institute of Nutrition Research University of Oslo Norway In the leukemic macrophage cell-line THP-1 a fraction of the secreted matrix metalloproteinase 9 MMP-9 is linked to the core protein of chondroitin sulfate proteoglycans CSPG . Unlike the monomeric and homodimeric forms of MMP-9 the addition of exogenous CaCl2 to the proMMP-9 CSPG complex resulted in an active gelatinase due to the induction of an autocatalytic removal of the N-terminal prodomain. In addition the MMP-9 was released from the CSPG through a process that appeared to be a stepwise truncation of both the CSPG core protein and a part of the C-terminal domain of the gelatinase. The calcium-induced activation and truncation of the MMP-9 CSPG complex was independent of the concentration of the complex inhibited by the MMP íhhibitors EDTA 1 10-phenanthroline and TIMP-1 but not by gnneral inhibitors of serine thiol and acid proteinases. This indicated that the activation and truncation process was not due to a bimolecular reaction but more likelyan intramolecular reaction. The negativelycharged chondroitin sulfate chains in the proteoglycan were not involved in this process. Other metal-containing compounds like aminophenylmercuric acetate TPMT NaCl ZnCl2 and MgCl2 were not able to induce activation and truncation of the proMMP-9 in this heterodimer. On the contrary TPMT inhibited the calcium-induced process whereas high concentrations of either MgCl2 or NaCl had no effect. Our results indicate that the interaction between the MMP-9 and the core protein of the CSPG was the causal factor in the calcium-induced activation and .