title: p63RhoGEF--a key mediator of angiotensin II-dependent signaling and processes in vascular smooth muscle cells.
abstract: The purpose of our study was to investigate the role of endogenous p63RhoGEF in G(q/11)-dependent RhoA activation and signaling in rat aortic smooth muscle cells (RASMCs). Therefore, we studied the expression and subcellular localization in freshly isolated RASMCs and performed loss of function experiments to analyze its contribution to RhoGTPase activation and functional responses such as proliferation and contraction. By this, we could show that p63RhoGEF is endogenously expressed in RASMCs and acts there as the dominant mediator of the fast angiotensin II (ANG II)-dependent but not of the sphingosine-1-phosphate (S(1)P)-dependent RhoA activation. p63RhoGEF is not an activator of the concomitant Rac1 activation and functions independently of caveolae. The knockdown of endogenous p63RhoGEF significantly reduced the mitogenic response of ANG II, abolished ANG II-induced stress fiber formation and cell elongation in 2-D culture, and impaired the ANG II-driven contraction in a collagen-based 3-D model. In conclusion, our data provide for the first time evidence that p63RhoGEF is an important mediator of ANG II-dependent RhoA activation in RASMCs and therewith a leading actor in the subsequently triggered cellular processes, such as proliferation and contraction.
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Wuertz
authors.forename: Akos
authors.initials: A
authors.lastname: Lorincz
authors.forename: Christiane
authors.initials: C
authors.lastname: Vettel
authors.forename: Martin A
authors.initials: MA
authors.lastname: Thomas
authors.forename: Thomas
authors.initials: T
authors.lastname: Wieland
authors.forename: Susanne
authors.initials: S
authors.lastname: Lutz
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D057912:Angiotensin II Type 2 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D001565:Benzoates / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D007150:Immunohistochemistry; D008246:Lysophospholipids / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000077333:Telmisartan
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D057912:Angiotensin II Type 2 Receptor Blockers; D001562:Benzimidazoles; D001565:Benzoates; D019332:Endothelin-1; D020662:Guanine Nucleotide Exchange Factors; D007093:Imidazoles; D008246:Lysophospholipids; D011725:Pyridines; D000804:Angiotensin II; C073402:PD 123319; C060506:sphingosine 1-phosphate; D012701:Serotonin; D013110:Sphingosine; D002118:Calcium; D000077333:Telmisartan