N-linked glycosylation of protease-activated receptor-1 at extracellular loop 2 regulates G-protein signaling bias.

Protease-activated receptor-1 (PAR1) is a G-protein-coupled receptor (GPCR) for the coagulant protease thrombin. Similar to other GPCRs, PAR1 is promiscuous and couples to multiple heterotrimeric G-protein subtypes in the same cell and promotes diverse cellular responses. The molecular mechanism by which activation of a given GPCR with the same ligand permits coupling to multiple G-protein subtypes is unclear.

Characterization of thrombin-bound dabigatran effects on protease-activated receptor-1 expression and signaling in vitro.

Thrombin, the key effector protease of the coagulation cascade, drives fibrin deposition and activates human platelets through protease-activated receptor-1 (PAR1). These processes are critical to the progression of thrombotic diseases. Thrombin is the main target of anticoagulant therapy, and major efforts have led to the discovery of new oral direct inhibitors of thrombin.

Regulation of protease-activated receptor signaling by post-translational modifications.

Protease-activated receptors (PARs) are a unique family of G-protein-coupled receptors (GPCRs) that are irreversibly activated following proteolytic cleavage of their extracellular N-terminus. PARs play critical functions in hemostasis, thrombosis, inflammation, embryonic development, and cancer progression. Because of the irreversible proteolytic nature of PAR activation, signaling by the receptors is tightly regulated.

N-linked glycosylation of protease-activated receptor-1 second extracellular loop: a critical determinant for ligand-induced receptor activation and internalization.

Protease-activated receptor-1 (PAR1) contains five N-linked glycosylation consensus sites as follows: three residing in the N terminus and two localized on the surface of the second extracellular loop (ECL2). To study the effect of N-linked glycosylation in the regulation of PAR1 signaling and trafficking, we generated mutants in which the critical asparagines of the consensus sites were mutated. Here, we report that both the PAR1 N terminus and ECL2 serve as sites for N-linked glycosylation but have different functions in the regulation of receptor signaling and trafficking.