Proteases Display Biased Agonism at Protease-Activated Receptors: Location matters!

Table 1.

Characteristics of the Four Protease-Activated Receptors

Receptor Tethered ligand Activating proteases Signaling effectors Shut-off mechanisms
1 Synthetic peptides that represent the newly formed N terminus can activate PARs independent of protease and cleavage with the exception of PAR3. 2 Shut-off mechanisms are best understood for PAR1 and PAR2, whereas activated PAR4 is not phosphorylated and its shut-off appears to mediated predominantly by internalization. Nothing is known about signal regulation of PAR3.
PAR1 SFLLRN Thrombin Gq Phosphorylation
TF-VIIa-Xa or Xa Gi β-Arrestins
APC-EPCR G12/13 Internalization
Trypsin Degradation
Plasmin
MMP1
Granzyme A
PAR2 SLIGKV Trypsin Gq Phosphorylation
Tryptase Gi β-Arrestins
TF-VIIa or TF-VIIa-Xa G12/13
Matriptase (MT-SP1) β-Arrestins
Der P3 D9
Bacterial gingipains-R
Kallikreins
Granzyme A
PAR3 TFRGAP1 Thrombin Gq ?2
PAR4 GYPGQV Thrombin Gq Internalization
Trypsin G12/13
TF-VIIa-Xa
Plasmin
Cathepsin G
Bacterial gingipains-R
Kallikreins

This Article

  1. MI April 2009 vol. 9 no. 2 87-96