Activation of the 92-kDa Gelatinase by Stromelysin and 4-Aminophenylmercuric Acetate
DIFFERENTIAL PROCESSING AND STABILIZATION OF THE CARBOXYL-TERMINAL DOMAIN BY TISSUE INHIBITOR OF METALLOPROTEINASES (TIMP) (*)
- Steven D. Shapiro(2)(3)(§),
- Catherine J. Fliszar(1),
- Thomas J. Broekelmann(2)(3),
- Robert P. Mecham(2)(3),
- Robert M. Senior(2) and
- Howard G. Welgus(1)
- From the (1)From theDivisions of Dermatology and
- (2)Respiratory/Critical Care, Department of Medicine, Washington University School of Medicine at Jewish Hospital and
- the (3)Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110
- § Recipient of a Career Investigator Award from the American Lung Association. To whom correspondence should be addressed: Respiratory and Critical Care Division, Jewish Hospital at Washington University Medical Center, St. Louis, MO 63110. Tel.: 314-454-7524; Fax: 314-454-8293.
Abstract
The matrix metalloproteinase 92-kDa gelatinase is a major product of inflammatory cells. Macrophages synthesize and secrete
this proteinase as a proenzyme in association with tissue inhibitor of metalloproteinases (TIMP) (92
), whereas neutrophils store and release it from secondary granules as a TIMP-free proenzyme (92
). Metalloproteinase proenzymes can be activated in vitro by a variety of agents, including organomercurials and proteinases, resulting in loss of an 8-10-kDa NH2-terminal domain which disrupts the interaction of a conserved cysteine residue with the catalytic zinc molecule. We report
that the activation and processing of 92-kDa gelatinase differs depending on its association with TIMP and the nature of the
activating agent. We observed that 92
undergoes classic activation to 82 kDa by stromelysin, whereas exposure to 4-aminophenylmercuric acetate (APMA) results in
a final product of 83 kDa that still contains the “prodomain” cysteine. Association with TIMP appears to stabilize the COOH-terminal
domain, whereas 92
is converted by APMA to a final product of 67 kDa lacking the COOH-terminal portion. In the continued presence of APMA, which
maintains cysteine-zinc disruption, the 67-kDa species is at least as active as the classic 82 kDa. In contrast, activation
of 92
by stromelysin initially generates the 82-kDa form which is followed by final conversion to a 50-kDa species that lacks the
catalytic domain of the parent molecule. Therefore, although stromelysin activation of 92
is initially efficient, the active 82-kDa form is short-lived and is replaced by an inactive 50-kDa product. This complex
pattern of activation of the 92-kDa gelatinase may serve to restrict its proteolytic capacity following exposure to stromelysin
and may serve to regulate proteinase activity in vivo.
Footnotes
-
↵* This work was supported by Grants RO-1 HL47328, HL2401, AR35805, PO-1 HL29594 and by the Montsanto-Searle/Washington University Biomedical Agreement. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- MMP
-
matrix metalloproteinase
- TIMP
-
tissue inhibitor of metalloproteinases
- APMA
-
4-aminophenylmercuric acetate
- PAGE
-
polyacrylamide gel electrophoresis
- HPLC
-
high performance liquid chromatography.
-
- Received December 29, 1994.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
