| Effect of a peptide inhibitor of protein kinase C on G-protein-mediated increase in myofilament Ca(2+)-sensitivity in rabbit arterial skinned muscle. | |
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MedLine Citation:
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PMID: 8012712 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. To investigate the role of protein kinase C in the increase mediated by guanosine 5'-triphosphate (GTP)-binding proteins (G-proteins) in the sensitivity of the contractile proteins to Ca2+ in vascular smooth muscle, the effect of a novel peptide inhibitor of protein kinase C (PKC19-36) on Ca(2+)-induced contraction and myosin light chain (MLC) phosphorylation was studied in the presence and absence of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) in beta-escin-skinned smooth muscle strips of rabbit mesenteric artery. For comparison, the effects were also observed of PKC19-36 on the action of phorbol 12,13-dibutylate (PDBu, an activator of PKC) on the two Ca(2+)-induced responses. 2. In beta-escin-skinned strips treated with ionomycin, Ca2+ (0.1-3 microM) concentration-dependently produced contraction in parallel with an increase in MLC-phosphorylation. GTP gamma S (10 microM) and PDBu (0.1 microM) each shifted both the Ca(2+)-force and Ca(2+)-MLC-phosphorylation relationships to the left without a significant change in either maximum response. The relationship between force and MLC-phosphorylation was not modified by either GTP gamma S or PDBu, indicating that the sensitivity of MLC-phosphorylation to Ca2+ is enhanced by both GTP gamma S and PDBu. 3. PKC19-36 itself modified neither the contraction nor MLC-phosphorylation induced by Ca2+ but it did block the PDBu-induced enhancement of these two Ca(2+)-induced responses. By contrast, PKC19-36 did not modify the GTP gamma S-induced enhancement of the two Ca(2+)-induced responses. Guanosine 5'-O-(2-thiodiphosphate) (GDP Beta S) attenuated the GTP gamma S-induced enhancement of the Ca2+-induced contraction.4. These results suggest that GTP gamma S increases Ca2+-induced MLC-phosphorylation through the activation of a PKC-independent mechanism and thus causes an increase in the sensitivity of the contractile proteins to Ca2+ in Beta-escin-skinned smooth muscle of rabbit mesenteric artery. |
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Authors:
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T Itoh; A Suzuki; Y Watanabe |
Publication Detail:
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Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: British journal of pharmacology Volume: 111 ISSN: 0007-1188 ISO Abbreviation: Br. J. Pharmacol. Publication Date: 1994 Jan |
Date Detail:
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Created Date: 1994-07-25 Completed Date: 1994-07-25 Revised Date: 2009-11-19 |
Medline Journal Info:
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Nlm Unique ID: 7502536 Medline TA: Br J Pharmacol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 311-7 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, Faculty of Medicine, Kyushu University, Fukuoka, Japan. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Binding Sites Calcium / pharmacology* Escin / chemistry GTP-Binding Proteins / metabolism* Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology Male Mesenteric Arteries / drug effects Microfilaments / drug effects*, metabolism Muscle Contraction / drug effects Muscle, Smooth, Vascular / drug effects*, metabolism Myosins / metabolism Peptide Fragments / pharmacology* Phorbol 12,13-Dibutyrate / pharmacology Phosphorylation Protein Kinase C / antagonists & inhibitors*, pharmacology* Rabbits |
| Chemical | |
Reg. No./Substance:
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0/Peptide Fragments; 0/protein kinase C (19-36); 37558-16-0/Phorbol 12,13-Dibutyrate; 37589-80-3/Guanosine 5'-O-(3-Thiotriphosphate); 6805-41-0/Escin; 7440-70-2/Calcium; EC 2.7.11.13/Protein Kinase C; EC 3.6.1.-/GTP-Binding Proteins; EC 3.6.4.1/Myosins |
| Comments/Corrections | |
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