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Published on: May 24, 2024
Engineering of substrate selectivity for tissue factor.factor VIIa complex signaling through protease-activated
Katrine S Larsen1, Henrik Ostergaard, Ole H Olsen
1Department of Haemostasis Biochemistry, Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Måløv, Denmark.
The Journal of Biological Chemistry
|April 15, 2010
Summary
Tissue factor (TF) and factor VIIa (FVIIa) complex initiates coagulation and signals through protease-activated receptor 2 (PAR2). Researchers identified key FVIIa residues crucial for PAR2 cleavage, revealing catalytic cleft interactions drive this signaling pathway.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Signaling
Background:
- The tissue factor (TF) and factor VIIa (FVIIa) complex is a key initiator of the coagulation cascade.
- TF.FVIIa also mediates cell signaling through protease-activated receptor 2 (PAR2), impacting cancer, angiogenesis, and inflammation.
- The precise molecular mechanisms of PAR2 cleavage by TF.FVIIa are not fully understood.
Purpose of the Study:
- To elucidate the molecular interactions between FVIIa and PAR2 during signaling.
- To identify specific FVIIa residues involved in PAR2 cleavage.
- To engineer protease-selective PAR2 receptors for further research.
Main Methods:
- Screening of FVIIa protease domain mutants.
- Analysis of PAR2 cleavage by wild-type and mutant FVIIa.
- Site-directed mutagenesis of PAR2 based on predicted interactions.
Main Results:
- Mutants Q40A, Q143N, and T151S in FVIIa impaired TF.FVIIa.PAR2 signaling but not coagulation substrate activation.
- Residues Q40, Q143, and T151 are located in the FVIIa S2' pocket, crucial for PAR2 recognition.
- PAR2 cleavage by TF.FVIIa involves catalytic cleft interactions, contrasting with exosite-mediated cleavage by thrombin on PAR1.
Conclusions:
- FVIIa utilizes catalytic cleft interactions, not exosites, for PAR2 recognition and cleavage.
- Specific FVIIa residues in the S2' pocket are critical for TF.FVIIa.PAR2 signaling.
- The findings enable the engineering of protease-selective PAR2 variants to study TF signaling in vivo.
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