Protease-activated receptor 3 is a second thrombin receptor in humans

Nature. 1997 Apr 3;386(6624):502-6. doi: 10.1038/386502a0.


Thrombin is a coagulation protease that activates platelets, leukocytes, endothelial and mesenchymal cells at sites of vascular injury, acting partly through an unusual proteolytically activated G-protein-coupled receptor. Knockout of the gene encoding this receptor provided definitive evidence for a second thrombin receptor in mouse platelets and for tissue-specific roles for different thrombin receptors. We now report the cloning and characterization of a new human thrombin receptor, designated protease-activated receptor 3 (PAR3). PAR3 can mediate thrombin-triggered phosphoinositide hydrolysis and is expressed in a variety of tissues, including human bone marrow and mouse megakaryocytes, making it a candidate for the sought-after second platelet thrombin receptor. PAR3 provides a new tool for understanding thrombin signalling and a possible target for therapeutics designed selectively to block thrombotic, inflammatory and proliferative responses to thrombin.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blood Platelets / metabolism*
  • COS Cells
  • Cloning, Molecular
  • DNA, Complementary
  • Endopeptidases / metabolism*
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Molecular Mimicry
  • Molecular Sequence Data
  • Mutation
  • RNA, Messenger / metabolism
  • Rats
  • Receptors, Thrombin / genetics
  • Receptors, Thrombin / metabolism*
  • Sequence Homology, Amino Acid
  • Signal Transduction
  • Thrombin / metabolism
  • Tissue Distribution


  • DNA, Complementary
  • RNA, Messenger
  • Receptors, Thrombin
  • protease-activated receptor 3
  • Endopeptidases
  • Thrombin

Associated data

  • GENBANK/U92971
  • GENBANK/U92972