The role of the C-terminal tail in protease-activated receptor-2-mediated Ca2+ signalling, proline-rich tyrosine kinase-2 activation, and mitogen-activated protein kinase activity.
C-terminal truncation mutants were made to investigate the role of the C-terminus in coupling proteinase-activated receptor-2 (PAR-2) to various signalling pathways. Membrane expression of the delta15, delta34, delta43, and delta34-43 mutants was similar; however, expression of deltatail was lost, as was agonist-mediated internalisation of deltatail, delta43, and delta34-43. Additionally, trypsin and SLIGKV-stimulated [3H]IP accumulation was abrogated in cells transiently expressing delta43 or delta34-43 truncations, but remained unaffected in cells expressing delta34 or delta15. PAR-2 agonist-stimulated intracellular Ca(2+) mobilisation and PYK-2 activity were also abolished by deltatail, delta43, and delta34-43 mutants. However, trypsin-stimulated stress-activated protein kinases (SAPKs) or extracellular signal-regulated kinase (ERK) activities were unaffected by the delta34-43 mutation, although activity was abrogated following delta43 or deltatail truncations, suggesting that Ca(2+) mobilisation, PYK-2, or receptor internalisation are not requied for activation of SAPKs or ERK. These studies identify a novel sequence within the PAR-2 C-terminus essential for InsP(3) generation and PYK-2 activity but not mitogen-activated protein kinase (MAPK) activation.
Seatter
Michael J
MJ
Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow, Scotland G4 ONR, UK.
Drummond
Robert
R
Kanke
Toru
T
Macfarlane
Scott R
SR
Hollenberg
Morley D
MD
Plevin
Robin
R
D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D019556:COS Cells; D020013:Calcium Signaling / Q000502:physiology*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D004705:Endocytosis / Q000502:physiology; D051418:Focal Adhesion Kinase 2; D007295:Inositol Phosphates / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D044464:Receptor, PAR-2 / Q000235:genetics / Q000378:metabolism*
D007295:Inositol Phosphates; D044464:Receptor, PAR-2; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases