Processing of Transforming Growth Factor 
1 Precursor by Human Furin Convertase (*)
- Claire M. Dubois(1)(§),
- Marie-Hélène Laprise(1)(2),
- Franois Blanchette(1),
- Larry E. Gentry(3)(¶) and
- Richard Leduc(2)(**)
- From the (1) Immunology Division, Department of Pediatrics, and
- (2) Department of Pharmacology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada and
- (3) Department of Biochemistry, Medical College of Ohio, Toledo, Ohio 43699
- § Research Scholar of the Fonds de la Recherche en Santé du Québec. To whom reprint requests should be addressed: Immunology Division, Dept. of Pediatrics, Faculty of Medicine, Université de Sherbrooke, 3001 N. 12th Ave., Sherbrooke, Québec J1H 5N4, Canada. Tel.: 819-563-5555 (ext. 4851); Fax: 819-564-5215; E mail: cmdubois{at}courrier.usherb.ca.
Abstract
Proteolytic processing of the transforming growth factor β precursor (pro-TGFβ) is an essential step in the formation of the biologically active TGFβ homodimeric protein (TGFβ). The 361-amino-acid precursor pro-TGFβ1 has within its primary structure the R-H-R-R processing signal found in many constitutively secreted precursor proteins and potentially recognized by members of the mammalian convertase family of endoproteases. To determine whether cleavage of pro-TGFβ1 can be achieved by the furin convertase in vitro, purified precursor was incubated in the presence of a truncated/secreted form of the enzyme. Immunoblots showed that the 55-kDa pro-TGFβ1 was converted into the 44 and 12.5 kDa bands corresponding to the pro-region and the mature monomer, respectively. Treatment of pro-TGFβ1 with furin resulted in a 5-fold increase in the production of biologically active TGFβ1. Furthermore, when expressed in the furin-deficient LoVo cells, no processing of pro-TGFβ1 was observed. In contrast, efficient processing was oberved when pro-TGFβ was coexpressed with the furin convertase. Collectively, these results provide evidence that in our experimental systems the TGFβ1 precursor is efficiently and correctly processed by human furin thus permitting release of the biologically active peptide.
Footnotes
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↵¶ Recipient of Grant A60848 from the National Institutes of Health.
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↵** Research Scholar of the Fonds de la Recherche en Santé du Québec.
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↵* 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. This work was supported by the Arthritis Society of Canada.
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↵1 The abbreviations used are:
- TGFβ
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transforming growth factor β
- VV
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Vaccinia virus
- WT
-
wild type
- HPLC
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high performance liquid chromatography
- PAGE
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polyacrylamide gel electrophoresis
- FUR
-
furin
- POMC
-
proopiomelanocortin
- CHO
-
Chinese hamster ovary.
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↵2 N. Seidah, personal communication.
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↵3 C. M. Dubois and N. Seidah, manuscript in preparation.
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↵4 Blanchette, F., Day, R., Laprise, M.-H. Grondin, F., and Dubois, C. M. (1995) FASEB J., in press.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
