Limiting angiotensin II signaling with a cell-penetrating peptide mimicking the second intracellular loop of the angiotensin II type-I receptor.
A cell-penetrating peptide consisting of the second intracellular loop (IC2) of the angiotensin II (AngII) type-I receptor (AT1) linked to the HIV-transactivating regulatory protein (TAT) domain was used to identify the role of this motif In intracellular signal transduction. HEK-293 cells stably transfected with AT1R cDNA and primary cultures of human pulmonary artery smooth muscle cells expressing endogenous AT1 receptor were exposed to the cell-penetrating peptide construct, and the effect on angiotensin II signaling was determined. The AT1 IC2 peptide effectively inhibited AngII-stimulated phosphatidylinositol turnover and calcium influx. It also limited the activation of Akt/PKB as determined by an inhibition of phosphorylation of Akt at Ser473, and completely abolished the AngII-dependent activation of the transcriptional factor NFkappaB. In contrast, the AT1 IC2 peptide had no effect on AngII/AT1 receptor activation of ERK. These results illustrate the potential of using cell-penetrating peptides to both delineate receptor-mediated signal transduction and to selectively regulate G protein-coupled receptor signaling.
Yu
Jun
J
Taylor
Linda
L
Mierke
Dale
D
Berg
Eric
E
Shia
Michael
M
Fishman
Jordan
J
Sallum
Christine
C
Polgar
Peter
P
D000804:Angiotensin II / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D011651:Pulmonary Artery / Q000166:cytology; D044140:Receptor, Angiotensin, Type 1 / Q000737:chemistry* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects*; D014162:Transfection; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry*
D010455:Peptides; D044140:Receptor, Angiotensin, Type 1; D054322:tat Gene Products, Human Immunodeficiency Virus; D000804:Angiotensin II