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Updated: Oct 1, 2026
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Published on: May 17, 2020
Identification and characterization of a novel rat ov-serpin family member, trespin
Jerry E Chipuk1, LaMonica V Stewart, Annalisa Ranieri
1Ireland Cancer Center Research Laboratories and Department of Pharmacology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, Ohio 44106, USA.
Abstract:
Serpins are responsible for regulating a variety of proteolytic processes through a unique irreversible suicide substrate mechanism. To discover novel genes regulated by transforming growth factor-beta1 (TGF-beta 1), we performed differential display reverse transcriptase-PCR analysis of NRP-152 rat prostatic epithelial cells and cloned a novel rat serpin that is transcriptionally down-regulated by TGF-beta and hence named trespin (TGF-beta-repressible serine proteinase inhibitor (trespin). Trespin is a 397-amino acid member of the ov-serpin clade with a calculated molecular mass of 45.2 kDa and 72% amino acid sequence homology to human bomapin; however, trespin exhibits different tissue expression, cellular localization, and proteinase specificity compared with bomapin. Trespin mRNA is expressed in many tissues, including brain, heart, kidney, liver, lung, prostate, skin, spleen, and stomach. FLAG-trespin expressed in HEK293 cells is localized predominantly in the cytoplasm and is not constitutively secreted. The presence of an arginine at the P1 position of trespin's reactive site loop suggests that trespin inhibits trypsin-like proteinases. Accordingly, in vitro transcribed and translated trespin forms detergent-stable and thermostable complexes with plasmin and elastase but not subtilisin A, trypsin, chymotrypsin, thrombin, or papain. Trespin interacts with plasmin at a near 1:1 stoichiometry, and immunopurified mammal-expressed trespin inhibits plasmin in a dose-dependent manner. These data suggest that trespin is a novel and functional member of the rat ov-serpin family.
Insights
Researchers discovered trespin, a novel rat serine proteinase inhibitor regulated by TGF-beta1. This proteinase inhibitor shows specific interactions with plasmin and elastase, suggesting a role in regulating proteolytic processes.
Area of Science:
- Molecular Biology
- Biochemistry
- Proteomics
Background:
- Serpins regulate proteolytic processes via a suicide substrate mechanism.
- Transforming growth factor-beta1 (TGF-beta1) is a key regulator of cellular processes.
Purpose of the Study:
- To identify novel genes regulated by TGF-beta1.
- To characterize a newly identified rat serpin, named trespin.
Main Methods:
- Differential display reverse transcriptase-PCR (DD-RT-PCR) was used to identify TGF-beta1-regulated genes.
- Cloning, sequencing, and expression of FLAG-trespin in HEK293 cells.
- In vitro assays to determine proteinase specificity and complex formation.
Main Results:
- A novel rat serpin, trespin, was identified and found to be transcriptionally down-regulated by TGF-beta1.
- Trespin shares homology with human bomapin but has distinct tissue expression, localization, and proteinase specificity.
- Trespin inhibits plasmin and elastase in vitro, forming stable complexes, and interacts with plasmin at a 1:1 stoichiometry.
Conclusions:
- Trespin is a novel, functional member of the rat ov-serpin family.
- Trespin's inhibition of plasmin suggests a role in regulating specific proteolytic pathways.
- Further research into trespin's function in vivo is warranted.
