Molecular Cloning and Characterization of Human Tissue Inhibitor of Metalloproteinase 4*
- From ‡ Human Genome Sciences, Inc., Rockville, Maryland 20850-3338 and
- § Department of Pediatrics, Long Island Jewish Medical Center, The Long Island Campus for the Albert Einstein College of Medicine, New Hyde Park, New York 11042
- ∥ To whom correspondence should be addressed: Pediatric Research Center, Schneider Children Hospital, Long Island Jewish Medical Center, New Hyde Park, NY 11042. Tel.: 718-470-3086; Fax: 718-470-6744; E-mail: Shi{at}aecom.yu.edu.
Abstract
The tissue inhibitors of metalloproteinases (TIMPs) constitute a family of proteins, of which three members have so far been described. Using the expressed sequence tag sequencing approach, we have identified a novel TIMP-related cDNA fragment and subsequently cloned a fourth human TIMP (TIMP-4) from a human heart cDNA library. The open reading frame encodes a 224-amino acid precursor including a 29-residue secretion signal. The predicted structure of the new protein shares 37% sequence identity with TIMP-1 and 51% identity with TIMP-2 and −3. The protein has a predicted isoelectric point of 7.34. The open reading frame-directed expression of TIMP-4 protein in MDA-MB-435 human breast cancer cells showed metalloproteinase inhibitory activity on reverse zymography. By Northern analysis, only the adult heart showed abundant TIMP-4 transcripts with a 1.4-kilobase predominant transcript band; very low levels of the transcripts were detected in the kidney, placenta, colon, and testes, and no transcripts were detected in the liver, brain, lung, thymus, and spleen. This unique expression pattern suggests that TIMP-4 may function in a tissue-specific fashion in extracellular matrix homeostasis.
Footnotes
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↵* This work was supported by Grant CA68064-01 from the National Institutes of Health, Grant DAMD17-94-J-4149 from the U.S. Department of the Army, and the Irving and Helen Schneider family.
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↵1 The abbreviations used are:
- MMP
-
matrix metalloproteinase
- TIMP
-
tissue inhibitor of metalloproteinases
- IMP
-
inhibitor of metalloproteases
- ECM
-
extracellular matrix
- EST
-
expressed sequence tag
- bp
-
base pair
- kb
-
kilobase.
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- Received April 5, 1996.
- Revision received August 5, 1996.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
