Protein kinase D selectively targets cardiac troponin I and regulates myofilament Ca2+ sensitivity in ventricular myocytes
Protein kinase D ( PKD) is a serine/threonine kinase with emerging myocardial functions; in skinned adult rat ventricular myocytes ( ARVMs), recombinant PKD catalytic domain phosphorylates cardiac troponin I at Ser22/Ser23 and reduces myofilament Ca2+ sensitivity. We used adenoviral gene transfer to...
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| Main Authors: | , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
22 February 2007
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| In: |
Circulation research
Year: 2007, Volume: 100, Issue: 6, Pages: 864-873 |
| ISSN: | 1524-4571 |
| DOI: | 10.1161/01.RES.0000260809.15393.fa |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1161/01.RES.0000260809.15393.fa
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| Author Notes: | Friederike Cuello, Sonya C. Bardswell, Robert S. Haworth, Xiaoke Yin, Susanne Lutz, Thomas Wieland, Manuel Mayr, Jonathan C. Kentish, Metin Avkiran |
| Summary: | Protein kinase D ( PKD) is a serine/threonine kinase with emerging myocardial functions; in skinned adult rat ventricular myocytes ( ARVMs), recombinant PKD catalytic domain phosphorylates cardiac troponin I at Ser22/Ser23 and reduces myofilament Ca2+ sensitivity. We used adenoviral gene transfer to determine the effects of full-length PKD on protein phosphorylation, sarcomere shortening and [ Ca2+](i) transients in intact ARVMs. In myocytes transduced to express wild-type PKD, the heterologously expressed enzyme was activated by endothelin 1 ( ET1) ( 5 nmol/L), as reflected by PKD phosphorylation at Ser744/Ser748 ( PKC phosphorylation sites) and Ser916 ( autophosphorylation site). The ET1-induced increase in cellular PKD activity was accompanied by increased cardiac troponin I phosphorylation at Ser22/Ser23; this measured approximately 60% of that induced by isoproterenol ( 10 nmol/L), which activates cAMP-dependent protein kinase ( PKA) but not PKD. Phosphorylation of other PKA targets, such as phospholamban at Ser16, phospholemman at Ser68 and cardiac myosin-binding protein C at Ser282, was unaltered. Furthermore, heterologous PKD expression had no effect on isoproterenol-induced phosphorylation of these proteins, or on isoproterenol-induced increases in sarcomere shortening and relaxation rate and [ Ca2+](i) transient amplitude. In contrast, heterologous PKD expression suppressed the positive inotropic effect of ET1 seen in control cells, without altering ET1-induced increases in relaxation rate and [ Ca2+](i) transient amplitude. Complementary experiments in "skinned" myocytes confirmed reduced myofilament Ca2+ sensitivity by ET1-induced activation of heterologously expressed PKD. We conclude that increased myocardial PKD activity induces cardiac troponin I phosphorylation at Ser22/Ser23 and reduces myofilament Ca2+ sensitivity, suggesting that altered PKD activity in disease may impact on contractile function. |
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| Item Description: | Gesehen am 24.03.2022 Im Text ist "2+" hochgestellt |
| Physical Description: | Online Resource |
| ISSN: | 1524-4571 |
| DOI: | 10.1161/01.RES.0000260809.15393.fa |