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Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA
We examined expression of protease-activated receptors 2 (PAR2) and characterized their signaling pathways in rabbit gastric muscle cells. The PAR2 activating peptide SLIGRL (PAR2-AP) stimulated G(q), G(13), G(i1), PI hydrolysis, and Rho kinase activity, and inhibited cAMP formation. Stimulation of...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3688948/ https://www.ncbi.nlm.nih.gov/pubmed/23825105 http://dx.doi.org/10.1371/journal.pone.0066743 |
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author | Sriwai, Wimolpak Mahavadi, Sunila Al-Shboul, Othman Grider, John R. Murthy, Karnam S. |
author_facet | Sriwai, Wimolpak Mahavadi, Sunila Al-Shboul, Othman Grider, John R. Murthy, Karnam S. |
author_sort | Sriwai, Wimolpak |
collection | PubMed |
description | We examined expression of protease-activated receptors 2 (PAR2) and characterized their signaling pathways in rabbit gastric muscle cells. The PAR2 activating peptide SLIGRL (PAR2-AP) stimulated G(q), G(13), G(i1), PI hydrolysis, and Rho kinase activity, and inhibited cAMP formation. Stimulation of PI hydrolysis was partly inhibited in cells expressing PAR2 siRNA, Ga(q) or Ga(i) minigene and in cells treated with pertussis toxin, and augmented by expression of dominant negative regulator of G protein signaling (RGS4(N88S)). Stimulation of Rho kinase activity was abolished by PAR-2 or Ga(13) siRNA, and by Ga(13) minigene. PAR2-AP induced a biphasic contraction; initial contraction was selectively blocked by the inhibitor of PI hydrolysis (U73122) or MLC kinase (ML-9), whereas sustained contraction was selectively blocked by the Rho kinase inhibitor (Y27632). PAR2-AP induced phosphorylation of MLC(20), MYPT1 but not CPI-17. PAR2-AP also caused a decrease in the association of NF-kB and PKA catalytic subunit: the effect of PAR2-AP was blocked by PAR2 siRNA or phosphorylation-deficient RhoA (RhoA(S188A)). PAR2-AP-induced degradation of IkBa and activation of NF-kB were abolished by the blockade of RhoA activity by Clostridium botulinum C3 exoenzyme suggesting RhoA-dependent activation of NF-kB. PAR2-AP-stimulated Rho kinase activity was significantly augmented by the inhibitors of PKA (myristoylated PKI), IKK2 (IKKIV) or NF-kB (MG132), and in cells expressing dominant negative mutants of IKK (IKK(K44A), IkBa (IkBa (S32A/S36A)) or RhoA(S188A), suggesting feedback inhibition of Rho kinase activity via PKA derived from NF-kB pathway. PAR2-AP induced phosphorylation of RhoA and the phosphorylation was attenuated in cells expressing phosphorylation-deficient RhoA(S188A). Our results identified signaling pathways activated by PAR2 to mediate smooth muscle contraction and a novel pathway for feedback inhibition of PAR2-stimulated RhoA. The pathway involves activation of the NF-kB to release catalytic subunit of PKA from its binding to IkBa and phosphorylation of RhoA at Ser(188). |
format | Online Article Text |
id | pubmed-3688948 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-36889482013-07-02 Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA Sriwai, Wimolpak Mahavadi, Sunila Al-Shboul, Othman Grider, John R. Murthy, Karnam S. PLoS One Research Article We examined expression of protease-activated receptors 2 (PAR2) and characterized their signaling pathways in rabbit gastric muscle cells. The PAR2 activating peptide SLIGRL (PAR2-AP) stimulated G(q), G(13), G(i1), PI hydrolysis, and Rho kinase activity, and inhibited cAMP formation. Stimulation of PI hydrolysis was partly inhibited in cells expressing PAR2 siRNA, Ga(q) or Ga(i) minigene and in cells treated with pertussis toxin, and augmented by expression of dominant negative regulator of G protein signaling (RGS4(N88S)). Stimulation of Rho kinase activity was abolished by PAR-2 or Ga(13) siRNA, and by Ga(13) minigene. PAR2-AP induced a biphasic contraction; initial contraction was selectively blocked by the inhibitor of PI hydrolysis (U73122) or MLC kinase (ML-9), whereas sustained contraction was selectively blocked by the Rho kinase inhibitor (Y27632). PAR2-AP induced phosphorylation of MLC(20), MYPT1 but not CPI-17. PAR2-AP also caused a decrease in the association of NF-kB and PKA catalytic subunit: the effect of PAR2-AP was blocked by PAR2 siRNA or phosphorylation-deficient RhoA (RhoA(S188A)). PAR2-AP-induced degradation of IkBa and activation of NF-kB were abolished by the blockade of RhoA activity by Clostridium botulinum C3 exoenzyme suggesting RhoA-dependent activation of NF-kB. PAR2-AP-stimulated Rho kinase activity was significantly augmented by the inhibitors of PKA (myristoylated PKI), IKK2 (IKKIV) or NF-kB (MG132), and in cells expressing dominant negative mutants of IKK (IKK(K44A), IkBa (IkBa (S32A/S36A)) or RhoA(S188A), suggesting feedback inhibition of Rho kinase activity via PKA derived from NF-kB pathway. PAR2-AP induced phosphorylation of RhoA and the phosphorylation was attenuated in cells expressing phosphorylation-deficient RhoA(S188A). Our results identified signaling pathways activated by PAR2 to mediate smooth muscle contraction and a novel pathway for feedback inhibition of PAR2-stimulated RhoA. The pathway involves activation of the NF-kB to release catalytic subunit of PKA from its binding to IkBa and phosphorylation of RhoA at Ser(188). Public Library of Science 2013-06-18 /pmc/articles/PMC3688948/ /pubmed/23825105 http://dx.doi.org/10.1371/journal.pone.0066743 Text en © 2013 Sriwai et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Sriwai, Wimolpak Mahavadi, Sunila Al-Shboul, Othman Grider, John R. Murthy, Karnam S. Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA |
title | Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA |
title_full | Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA |
title_fullStr | Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA |
title_full_unstemmed | Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA |
title_short | Distinctive G Protein-Dependent Signaling by Protease-Activated Receptor 2 (PAR2) in Smooth Muscle: Feedback Inhibition of RhoA by cAMP-Independent PKA |
title_sort | distinctive g protein-dependent signaling by protease-activated receptor 2 (par2) in smooth muscle: feedback inhibition of rhoa by camp-independent pka |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3688948/ https://www.ncbi.nlm.nih.gov/pubmed/23825105 http://dx.doi.org/10.1371/journal.pone.0066743 |
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