Endothelin A and endothelin B receptors differ in their ability to stimulate ERK1/2 activation.
Endothelin-1 (ET-1) acts on two different G protein-coupled receptors, namely the endothelin A (ET(A)) and the endothelin B (ET(B)) receptors. Both receptor subtypes show differences in their tissue expression and signal transduction. In the present study, we compared the ability of ET(A) and ET(B) receptors to stimulate extracellular signal-regulated kinase 1/2 (ERK1/2). In addition, we analyzed the role of the extracellular N terminus for ERK1/2 activation, because the ET(B) receptor undergoes an agonist-dependent N-terminal proteolysis. ET-1 stimulation of HEK293 cells stably expressing the ET(A) receptor induced a monophasic, but sustained ERK1/2 activation, whereas the ET(B) receptor showed a biphasic ERK1/2 activation. A truncated mutant ET(B) receptor, lacking the proteolytically cleaved N terminus (delta2-64 ET(B)) revealed only a monophasic and transient ERK1/2 activation. Treatment of HEK293 delta2-64 ET(B) cell clones with ET-1 and a synthetic NT27-64 peptide, corresponding to the N-terminally cleaved fragment of the ET(B) receptor and ET-1, did not restore the biphasic activation of ERK1/2. A chimeric ET(B) receptor in which the N terminus was replaced by the N terminus of the ET(A) receptor elicited biphasic ERK1/2 activation. The presented data suggest that an intact N terminus of the ET(B) receptor is necessary for the second phase of ERK1/2 activation. However, it appears that the length of the N terminus rather than a specific sequence motif is required for biphasic ERK1/2 activation.
Grantcharova
Evelina
E
Institut für Pharmakologie, Charité Campus Benjamin Franklin, Thielallee 67-73, 14195 Berlin, Germany.
Reusch
H Peter
HP
Beyermann
Michael
M
Rosenthal
Walter
W
Oksche
Alexander
A
D002460:Cell Line; D019332:Endothelin-1 / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006031:Glycosylation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D044022:Receptor, Endothelin A / Q000378:metabolism*; D044023:Receptor, Endothelin B / Q000737:chemistry* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection
D019332:Endothelin-1; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D049452:Green Fluorescent Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3