Proteinase-activated receptors: transducers of proteinase-mediated signaling in inflammation and immune response.
Serine proteinases such as thrombin, mast cell tryptase, trypsin, or cathepsin G, for example, are highly active mediators with diverse biological activities. So far, proteinases have been considered to act primarily as degradative enzymes in the extracellular space. However, their biological actions in tissues and cells suggest important roles as a part of the body's hormonal communication system during inflammation and immune response. These effects can be attributed to the activation of a new subfamily of G protein-coupled receptors, termed proteinase-activated receptors (PARs). Four members of the PAR family have been cloned so far. Thus, certain proteinases act as signaling molecules that specifically regulate cells by activating PARs. After stimulation, PARs couple to various G proteins and activate signal transduction pathways resulting in the rapid transcription of genes that are involved in inflammation. For example, PARs are widely expressed by cells involved in immune responses and inflammation, regulate endothelial-leukocyte interactions, and modulate the secretion of inflammatory mediators or neuropeptides. Together, the PAR family necessitates a paradigm shift in thinking about hormone action, to include proteinases as key modulators of biological function. Novel compounds that can modulate PAR function may be potent candidates for the treatment of inflammatory or immune diseases.
Steinhoff
Martin
M
Department of Dermatology and Boltzmann Institute for Immunobiology of the Skin, University of Münster, von-Esmarch-Strasse 58, 48149 Münster, Germany. msteinho@uni-muenster.de
Buddenkotte
Jörg
J
Shpacovitch
Victoria
V
Rattenholl
Anke
A
Moormann
Corinna
C
Vergnolle
Nathalie
N
Luger
Thomas A
TA
Hollenberg
Morley D
MD
D000595:Amino Acid Sequence; D000818:Animals; D001792:Blood Platelets; D002318:Cardiovascular Diseases / Q000188:drug therapy; D042783:Endothelial Cells; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D007109:Immunity; D007249:Inflammation; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010447:Peptide Hydrolases / Q000502:physiology*; D044462:Receptors, Proteinase-Activated / Q000032:analysis / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013045:Species Specificity
D044462:Receptors, Proteinase-Activated; D010447:Peptide Hydrolases; D019204:GTP-Binding Proteins