Regulation of Human ADAM 12 Protease by the Prodomain
EVIDENCE FOR A FUNCTIONAL CYSTEINE SWITCH*
- From the ‡Institute of Molecular Pathology, University of Copenhagen, Copenhagen DK-2100, and the ¶Department of Molecular and Structural Biology, University of Aarhus, Aarhus, Denmark DK-8000
Abstract
The ADAMs (a disintegrinand metalloprotease) are a family of multidomain proteins that are believed to play key roles in cell-cell and cell-matrix interactions. We have shown recently that human ADAM 12-S (meltrin α) is an active metalloprotease. It is synthesized as a zymogen, with the prodomain maintaining the protease in a latent form. We now provide evidence that the latency mechanism of ADAM 12 can be explained by the cysteine switch model, in which coordination of Zn2+ in the active site of the catalytic domain by a cysteine residue in the prodomain is critical for inhibition of the protease. Replacing Cys179 with other amino acids results in an ADAM 12 proform that is proteolytically active, but latency can be restored by placing cysteine at other positions in the propeptide. None of the amino acids adjacent to the crucial cysteine residue is essential for blocking activity of the protease domain. In addition to its latency function, the prodomain is required for exit of ADAM 12 protease from the endoplasmic reticulum. Tissue inhibitor of metalloprotease-1, -2, and -3 were not found to block proteolytic activity of ADAM 12, hence a physiological inhibitor of ADAM 12 protease in the extracellular environment remains to be identified.
Footnotes
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↵* This work was supported in part by grants from the Danish Cancer Society, the Danish Medical Research Council, and the VELUX, Novo-Nordisk, Munksholm, Haensch, Thaysen, Wærum, Bojesen, Beckett, Hartmann, and Meyer Foundations (to U. M. W., and R. A.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵§ Supported by a fellowship from the Danish Cancer Society.
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↵‖ To whom correspondence should be addressed: Institute of Molecular Pathology, University of Copenhagen, Frederik V’s Vej 11, DK-2100, Copenhagen, Denmark. Tel.: 45-3532-6056; Fax: 45-3532-6081; E-mail: molera{at}inet.uni-c.dk.
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↵2 F. Loechel and U. M. Wewer, unpublished observations.
- Abbreviations:
- ADAM
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a disintegrin and metalloprotease
- α2M
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α2-macroglobulin
- MMP
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matrix metalloprotease
- NEM
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N-ethylmaleimide
- TIMP
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tissue inhibitor of metalloprotease
- PAGE
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polyacrylamide gel electrophoresis
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- Received December 30, 1998.
- Revision received February 4, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
