8C). mechanisms regulating blood pressure by stimulating the contraction of vascular clean muscle mass cells and water reabsorption in the kidney [1C7]. Importantly, AVP functions as a growth element inducing hypertrophy and cell growth in a variety of cell types [8C13]. AVP-stimulated cellular reactions are mediated by three AVP receptors subtypes (V1, V2 and V3), which belong to the superfamily of G-protein-coupled receptors (GPCRs). Like many GPCRs, the V1 receptor transactivates the EGF receptor (EGFR) to induce the manifestation of immediate early genes leading to the cell cycle progression and growth [14C19]. GPCRs transactivate EGFR via several mechanisms [20, 21]. One mechanism entails the activation of a membrane-bound metalloproteinase that catalyzes the extracellular dropping of HB-EGF, which then actives the EGFR [22C25]. A second mechanism entails the activation of c-Src, which leads to the phosphorylation and activation of EGFR [26C28]. Additionally, tyrosine kinase receptors can use GPCR-mediated signalling pathways to stimulate downstream effectors, such as ERK1/2 . This mechanism of cross-talk between tyrosine kinase receptors and the GPGRs has been designated as integrative signalling [29, 30]. Since the growth of the clean muscle cell is definitely important for the arterial wall stiffness and for the onset of hypertension, we investigated L-Tyrosine the mechanisms of the AVP triggered-expression of two growth-related genes c-Fos and the early growth response gene 1 (Egr-1) in A-10 cells. This cell collection is derived from rat clean muscle cells, which endogenously communicate both V1 and EGF receptors. In this work we showed that AVP-induced up-regulation of c-Fos and Egr-1 is definitely mediated from the activation of two L-Tyrosine unique EGFR transactivation mechanisms. 2. Material and methods 2.1 Materials Dulbeccos modified Eagles medium (DMEM), penicillin, streptomycin, glutamine, and fungizone were from Invitrogen. Phorbol, 12-myristate, 13-acetate, GF109203X, PD98059, Y27632, PP1 and AG 1478 were from Calbiochem. GM6001 was from Chemicon. MMP Inhibitor III was from Merck. Ultraspec was from Biotecx. Pertussis toxin was from Biomol International. Antibody against phospho-retinoblastoma protein was from Cell L-Tyrosine Signaling Technology, anti-Egr-1 and anti c-Fos were from Santa Cruz Biotechnology. The V1 antagonist d(CH2)5[Tyr2(Me)Tyr9(NH2)]AVP was kindly provided by Prof. M. Manning (Medical College of Ohio, Toledo, USA). The siRNA for -arrestin 2 was purchased from Invitrogen. 2.2. Manifestation vectors Plasmids encoding crazy type c-Src and c-SrcK295R/Y527F were a generous gift from Dr. Joan S. Brugge (Harvard Medical School, USA). The plasmid encoding L61S186Ras was generously provided by Dr. Kun-Liang Guan (University or college of Michigan Medical School, USA). The EGFR dominating bad mutant HERCD533 was generously provided by Dr. S Meloche (University or college of Montreal, Quebec, Canada). The plasmid encoding the C-terminus of -adrenergic receptor kinase (CT-GRK2) was a nice gift from Dr. Juan Olate (Universidad de Concepcin, Chile). The plasmid encoding the S1 catalytic subunit of Pertussis toxin was kindly provided by Dr. Halvard Bonig (University or college of Washington, USA) 2.3. Cell tradition and transfections The clean muscle cell collection A-10 (ATCC CRL 1476) was cultured to subconfluency on 35 mm dishes in DMEM comprising 10% FBS. Serum starved cells were treated with vasopressin in the absence and presence of inhibitors. The reaction was halted by addition of 100 l of ice-cold RIPA buffer (150 mM NaCl, Tris/ HCl pH 8.0, 1% deoxycholic acid, 1% Nonidet P40, 0.1% SDS, 4 mM EDTA, 1 mM Na3VO4, 250 g/ml p-nitrophenyl phosphate, 1 mM phenylmethane-sulphonyl fluoride, 1 g/ml each of leupeptin, pepstatin A and aprotinin). Cells were lysed and proteins were precipitated by addition of trichloroacetic acid and resuspended in electrophoresis sample buffer comprising 1 mM Na3VO4. In some experiments, cells were incubated with the V1 antagonist d(CH2)5[Tyr2(Me)Tyr9(NH2)]AVP, GF109203X or with PD98059 or with AG 1478 or with MMP or GM6001 inhibitors prior the activation with AVP. Transient transfections were carried out using FuGENE 6 Transfection Reagent (Roche Diagnostics). The siRNA for arrestin 2 was transfected using Block-iT Transfection Kit (Invitrogen). 2.4 Rabbit Polyclonal to TCEAL4 European blotting Cell extracts were fractionated using SDS-PAGE, and the proteins were electrotransferred onto nitrocellulose filters using L-Tyrosine 0.05% SDS in the transfer buffer (20 mM Tris-glicine pH 8.3 and 20% methanol). Blots were incubated with anti c-Fos or anti Egr-1 or anti phospho-retinoblastoma.