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Updated: May 21, 2026

Characterizing Modulators of Protease-Activated Receptors with a Calcium Mobilization Assay Using a Plate Reader
Published on: May 24, 2024
Allosteric modulation of protease-activated receptor signaling
1Department of Pharmacology, School of Medicine, University of California, San Diego, Biomedical Sciences Building, Room 3044A, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA. joanntrejo@ucsd.edu
Protease-activated receptors (PARs) are GPCRs activated by proteolysis. Novel research reveals PARs can be differentially activated, leading to distinct cellular responses through allosteric modulation.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Protease-activated receptors (PARs) are G protein-coupled receptors (GPCRs) activated by proteolysis.
- PARs play crucial roles in hemostasis, thrombosis, inflammation, embryonic development, and cancer progression.
- The PAR family comprises four members: PAR1, PAR2, PAR3, and PAR4.
Purpose of the Study:
- To discuss mechanisms underlying the allosteric modulation of PAR signaling.
- To highlight how PARs can be differentially activated, leading to distinct cellular outcomes.
Main Methods:
- Review of recent studies on PAR activation mechanisms.
- Discussion of allosteric modulation, including protease activation, peptide agonists, dimerization, and caveolae compartmentalization.
Main Results:
- PARs possess a cryptic N-terminal ligand sequence exposed by proteolysis.
- Contrary to initial assumptions, PAR activation is not uniform across different proteases.
- Differential activation by synthetic agonists, proteases, or dimerization leads to distinct cellular responses.
- Allosteric modulation can involve compartmentalization within caveolae.
Conclusions:
- PAR signaling is more complex than initially proposed, with diverse activation pathways.
- Allosteric modulation offers a nuanced understanding of PAR function in various physiological and pathological processes.
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