The thrombin receptor is structurally related to other members of the 7-transmembrane receptor family and has
been isolated from diverse cell types. It is intimately involved in the regulation of the thrombotic response.
NCBI Summary:
Coagulation factor II receptor is a 7-transmembrane receptor involved in the regulation of thrombotic response. Proteolytic cleavage leads to the activation of the receptor. F2R is a G-protein coupled receptor family member.
Lindsay E. Roach et al 2002 reported thrombin generation and presence of Thrombin Receptor in Ovarian Follicles.
Prothrombin, once converted to its enzymatically active form (i.e., thrombin), induces a broad spectrum of cellular responses in both vascular and avascular tissues. Bovine ovarian granulosa cells isolated from healthy follicles of various sizes contain both prothrombin mRNA and immunologically reactive prothrombin that appears to be identical to prothrombin in follicular fluid and plasma. When tissue factor, the primary physiological activator of thrombin generation in plasma, is used to initiate thrombin formation, the profile of prothrombin-to-thrombin conversion is similar in follicular fluid and plasma. The conclusion that biologically functional prothrombin is synthesized by granulosa cells is further supported by evidence that mRNA for -glutamyl carboxylase, an enzyme essential for the vitamin K-dependent posttranslational modification of prothrombin, is expressed in granulosa cells in a manner similar to prothrombin mRNA. Thrombin's biological effects are mediated through selective proteolytic cleavage and activation of specific receptors. Bovine granulosa cells possess thrombin receptor (PAR-1) mRNA, and as seen with prothrombin mRNA and -glutamyl carboxylase mRNA, cells isolated from small follicles possess more PAR-1 mRNA than cells from large follicles. Thrombin receptor expression by cells in close proximity to an active thrombin-generating system suggests that these factors may be important mediators of cellular function in the ovarian follicle.
Follicle stages
Secondary, Antral
Comment
The presence of thrombin and its receptor, protease-activated receptor 1 (PAR 1), in the ovary suggests that thrombin may regulate ovarian function. In particular, to address the possible role of thrombin in ovulation, a phenomenon displaying mimicry of inflammation, Hirota Y, et al investigated the effects of thrombin and PAR 1 on the production of inflammation-related substances in human luteinized granulosa cells (LGC). Thrombin stimulated the production of IL-8 and monocyte chemoattractant protein-1 by cultured LGC. The stimulatory effects of thrombin were inhibited by both inhibitors of thrombin (hirudin and PPACK) and a protein kinase C inhibitor (calphostin C). The PAR 1 agonist, SFLLRN, also stimulated the production of IL-8 and monocyte chemoattractant protein-1. Thrombin and SFLLRN stimulated the geletinase activities of LGC, the effect of both being inhibited by hirudin and PPACK. Immunocytochemical study showed that thrombin and SFLLRN induced translocation of nuclear factor kappaB to the nucleus from the cytoplasm in LGC. Expression of PAR 1 mRNA was detected in LGC by RT-PCR analysis. These findings suggest that thrombin plays physiological roles in ovulation by enhancing the production of chemoattractive and gelatinolytic substances by granulosa cells by a mechanism involving PAR 1.
Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: embryonic lethal Comment: Approximately one-half of Par1 -/- embryos died at midgestation with bleeding from multiple
sites. Griffin et al .