ArticleJournal of muscle research and cell motility2011
Protein phosphatase 2A affects myofilament contractility in non-failing but not in failing human myocardium.
Article in Journal of muscle research and cell motility, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 33 papers.
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Who cites it
33 citing papers in PubMed, 57 citations in OpenAlex.
- Protein phosphatase 2A is regulated by protein kinase Cα (PKCα)-dependent phosphorylation of its targeting subunit B56α at Ser41.The Journal of biological chemistry · 2014Trial
- Troponin I - a comprehensive review of its function, structure, evolution, and role in muscle diseases.Animal cells and systems · 2025Review
- Further investigations on the influence of protein phosphatases on the signaling of muscarinic receptors in the atria of mouse hearts.Naunyn-Schmiedeberg's archives of pharmacology · 2024Article
- Loss of protein phosphatase 2A regulatory subunitFrontiers in cardiovascular medicine · 2024Article
- Cantharidin increases the force of contraction and protein phosphorylation in isolated human atria.Naunyn-Schmiedeberg's archives of pharmacology · 2023Article
- Protein Phosphatase 2A Improves Cardiac Functional Response to Ischemia and Sepsis.International journal of molecular sciences · 2022Article
- Serine-threonine protein phosphatase regulation of Cx43 dephosphorylation in arrhythmogenic disorders.Cellular signalling · 2021Review
- Hypoxia modulates protein phosphatase 2A through HIF-1α dependent and independent mechanisms in human aortic smooth muscle cells and ventricular cardiomyocytes.British journal of pharmacology · 2019Article
- Phosphodiesterase 5 inhibition improves contractile function and restores transverse tubule loss and catecholamine responsiveness in heart failure.Scientific reports · 2019Article
- Role of type 2A phosphatase regulatory subunit B56α in regulating cardiac responses to β-adrenergic stimulation in vivo.Cardiovascular research · 2019Article
- PP2A negatively regulates the hypertrophic response by dephosphorylating HDAC2 S394 in the heart.Experimental & molecular medicine · 2018Article
- The continuing evolution of cardiac troponin I biomarker analysis: from protein to proteoform.Expert review of proteomics · 2017Review
- Posttranslational modifications of calcium/calmodulin-dependent protein kinase IIδ and its downstream signaling in human failing hearts.American journal of translational research · 2017Article
- Roles and regulation of protein phosphatase 2A (PP2A) in the heart.Journal of molecular and cellular cardiology · 2016Review
- Regulation of sarcoplasmic reticulum CaJournal of molecular and cellular cardiology · 2016Review
- Myofilament Calcium Sensitivity: Role in Regulation ofFrontiers in physiology · 2016Review
- Removal of Abnormal Myofilament O-GlcNAcylation Restores Ca2+ Sensitivity in Diabetic Cardiac Muscle.Diabetes · 2015Article
- Protein phosphatase 2A regulatory subunit B56α limits phosphatase activity in the heart.Science signaling · 2015Article
- Development of phosphatase inhibitor-1 peptides acting as indirect activators of phosphatase 1.Naunyn-Schmiedeberg's archives of pharmacology · 2015Article
- Independent modulation of contractile performance by cardiac troponin I Ser43 and Ser45 in the dynamic sarcomere.Journal of molecular and cellular cardiology · 2015Article
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Authors and funding
11 authors at 4 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Protein phosphatase (PP) type 2A is a multifunctional serine/threonine phosphatase that is involved in cardiac excitation-contraction coupling. The PP2A core enzyme is a dimer, consisting of a catalytic C and a scaffolding A subunit, which is targeted to several cardiac proteins by a regulatory B subunit. At present, it is controversial whether PP2A and its subunits play a critical role in end-stage human heart failure. Here we report that the application of purified PP2AC significantly increased the Ca2+-sensitivity (ΔpCa50=0.05±0.01) of the contractile apparatus in isolated skinned myocytes of non-failing (NF) hearts. A higher phosphorylation of troponin I (cTnI) was found at protein kinase A sites (Ser23/24) in NF compared to failing myocardium. The basal Ca2+-responsiveness of myofilaments was enhanced in myocytes of ischemic (ICM, ΔpCa50=0.10±0.03) and dilated (DCM, ΔpCa50=0.06±0.04) cardiomyopathy compared to NF. However, in contrast to NF myocytes the treatment with PP2AC did not shift force-pCa relationships in failing myocytes. The higher basal Ca2+-sensitivity in failing myocytes coincided with a reduced protein expression of PP2AC in left ventricular tissue from patients suffering from ICM and DCM (by 50 and 56% compared to NF, respectively). However, PP2A activity was unchanged in failing hearts despite an increase of both total PP and PP1 activity. The expression of PP2AB56α was also decreased by 51 and 62% in ICM and DCM compared to NF, respectively. The phosphorylation of cTnI at Ser23/24 was reduced by 66 and 49% in ICM and DCM compared to NF hearts, respectively. Our results demonstrate that PP2A increases myofilament Ca2+-sensitivity in NF human hearts, most likely via cTnI dephosphorylation. This effect is not present in failing hearts, probably due to the lower baseline cTnI phosphorylation in failing compared to non-failing hearts.
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