FXYD1 phosphorylation in vitro and in adult rat cardiac myocytes: threonine 69 is a novel substrate for protein kinase C

Fuller, William; Howie, J. W.; McLatchie, Linda M.; Weber, Roberta; Hastie, C. James; Burness, Kerry; Pavlović, Davor; Shattock, Michael J.

doi:10.1152/ajpcell.00523.2008

Cited by 70 publications

(125 citation statements)

References 34 publications

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“…ϩ -K ϩ pump inhibition mediated by cAMP-dependent pathways in cardiac myocytes was reported in early studies (8,9), but many more recent studies have reported that these pathways mediate pump stimulation either by increasing maximal pump rate or by increasing pump affinity for intracellular Na ϩ (7,(11)(12)(13)(14)(15)(16)30). In our study, forskolin induced glutathionylation of the Na ϩ -K ϩ pump ␤ 1 subunit.…”

Section: Nasupporting

confidence: 52%

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Activation of cAMP-dependent Signaling Induces Oxidative Modification of the Cardiac Na+-K+ Pump and Inhibits Its Activity

White

Liu

García

et al. 2010

Journal of Biological Chemistry

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Cellular signaling can inhibit the membrane Na؉ -K ؉ pump via protein kinase C (PKC)-dependent activation of NADPH oxidase and a downstream oxidative modification, glutathionylation, of the ␤ 1 subunit of the pump ␣/␤ heterodimer. It is firmly established that cAMP-dependent signaling also regulates the pump, and we have now examined the hypothesis that such regulation can be mediated by glutathionylation. Exposure of rabbit cardiac myocytes to the adenylyl cyclase activator forskolin increased the co-immunoprecipitation of NADPH oxidase subunits p47 phox and p22 phox , required for its activation, and increased superoxide-sensitive fluorescence. Forskolin also increased glutathionylation of the Na ؉ -K ؉ pump ␤ 1 subunit and decreased its co-immunoprecipitation with the ␣ 1 subunit, findings similar to those already established for PKC-dependent signaling. The decrease in co-immunoprecipitation indicates a decrease in the ␣ 1 /␤ 1 subunit interaction known to be critical for pump function. In agreement with this, forskolin decreased ouabain-sensitive electrogenic Na ؉ -K ؉ pump current (arising from the 3:2 Na ؉ :K ؉ exchange ratio) of voltage-clamped, internally perfused myocytes. The decrease was abolished by the inclusion of superoxide dismutase, the inhibitory peptide for the ⑀-isoform of PKC or inhibitory peptide for NADPH oxidase in patch pipette solutions that perfuse the intracellular compartment. Pump inhibition was also abolished by inhibitors of protein kinase A and phospholipase C. We conclude that cAMPand PKC-dependent inhibition of the cardiac Na ؉ -K ؉ pump occurs via a shared downstream oxidative signaling pathway involving NADPH oxidase activation and glutathionylation of the pump ␤ 1 subunit.

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Section: Nasupporting

confidence: 52%

“…We have found the ␤ 3 adrenergic receptor mediates stimulation of the Na ϩ -K ϩ pump in cardiac myocytes (5). 5 We, therefore, used forskolin, as have most of the recent studies (7,11,12,15,16).…”

Section: Namentioning

confidence: 99%

Activation of cAMP-dependent Signaling Induces Oxidative Modification of the Cardiac Na+-K+ Pump and Inhibits Its Activity

White

Liu

García

et al. 2010

Journal of Biological Chemistry

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“…Drugs, Antibodies, and Chemicals-Antibodies to the PLM N terminus (raised in chickens) and PLM phosphorylation sites (raised in sheep) are described elsewhere (4,6). Anti-phospholamban raised in mice was from Millipore, and anti-caveolin 3 raised in mice was from BD Biosciences.…”

Section: Methodsmentioning

confidence: 99%

“…In cardiac myocytes, the sodium pump associates with FXYD1 (phospholemman (PLM) 3 ) (3,4), which was first recognized as an abundant phosphoprotein in the cardiac sarcolemma (5). Acute regulation of the cardiac sodium pump by the adrenergic system is through phosphorylation of PLM (4, 6 -10), which is unique in the FXYD family in having multiple phosphorylation sites on its intracellular C terminus (6,11). Unphosphorylated PLM inhibits the cardiac sodium pump by reducing its sodium affinity (8 -10, 12) and V max (4,6,7,13), and phosphorylation of PLM by PKA (on serine 68) or PKC (on serines 63 and 68 and threonine 69) relieves this inhibition (8,9) and in some models actually increases V max of the pump (4,10,13).…”

mentioning

confidence: 99%

“…Acute regulation of the cardiac sodium pump by the adrenergic system is through phosphorylation of PLM (4, 6 -10), which is unique in the FXYD family in having multiple phosphorylation sites on its intracellular C terminus (6,11). Unphosphorylated PLM inhibits the cardiac sodium pump by reducing its sodium affinity (8 -10, 12) and V max (4,6,7,13), and phosphorylation of PLM by PKA (on serine 68) or PKC (on serines 63 and 68 and threonine 69) relieves this inhibition (8,9) and in some models actually increases V max of the pump (4,10,13). Activation of the cardiac sodium pump via phosphorylation of PLM is necessary to protect against catecholamine-induced sodium and calcium overload, which leads to cardiac arrhythmias in vivo (14).…”

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confidence: 99%

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The Inhibitory Effect of Phospholemman on the Sodium Pump Requires Its Palmitoylation

Tulloch

Howie

Wypijewski

et al. 2011

Journal of Biological Chemistry

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Background: Phospholemman regulates the plasmalemmal sodium pump in excitable tissues such as the heart. Results: Phospholemman is palmitoylated at two intracellular cysteines, and this reduces ion transport by the sodium pump. Conclusion: Phospholemman must be palmitoylated to inhibit the sodium pump. Significance: This is a potentially new way to regulate the sodium pump, an enzyme expressed in most eukaryotic cells.

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Coordinated Regulation of Cardiac Na+/Ca2+ Exchanger and Na+-K+-ATPase by Phospholemman (FXYD1)

Cheung

Zhang

Song

et al. 2012

Advances in Experimental Medicine and Biology

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Phospholemman (PLM) is the founding member of the FXYD family of regulators of ion transport. PLM is a 72-amino acid protein consisting of the signature PFXYD motif in the extracellular N terminus, a single transmembrane (TM) domain, and a C-terminal cytoplasmic tail containing three phosphorylation sites. In the heart, PLM co-localizes and co-immunoprecipitates with Na(+)-K(+)-ATPase, Na(+)/Ca(2+) exchanger, and L-type Ca(2+) channel. The TM domain of PLM interacts with TM9 of the α-subunit of Na(+)-K(+)-ATPase, while its cytoplasmic tail interacts with two small regions (spanning residues 248-252 and 300-304) of the proximal intracellular loop of Na(+)/Ca(2+) exchanger. Under stress, catecholamine stimulation phosphorylates PLM at serine(68), resulting in relief of inhibition of Na(+)-K(+)-ATPase by decreasing K(m) for Na(+) and increasing V(max), and simultaneous inhibition of Na(+)/Ca(2+) exchanger. Enhanced Na(+)-K(+)-ATPase activity lowers intracellular Na(+), thereby minimizing Ca(2+) overload and risks of arrhythmias. Inhibition of Na(+)/Ca(2+) exchanger reduces Ca(2+) efflux, thereby preserving contractility. Thus, the coordinated actions of PLM during stress serve to minimize arrhythmogenesis and maintain inotropy. In acute cardiac ischemia and chronic heart failure, either expression or phosphorylation of PLM or both are altered. PLM regulates important ion transporters in the heart and offers a tempting target for development of drugs to treat heart failure.

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FXYD1 phosphorylation in vitro and in adult rat cardiac myocytes: threonine 69 is a novel substrate for protein kinase C

Cited by 70 publications

References 34 publications

Activation of cAMP-dependent Signaling Induces Oxidative Modification of the Cardiac Na+-K+ Pump and Inhibits Its Activity

Activation of cAMP-dependent Signaling Induces Oxidative Modification of the Cardiac Na+-K+ Pump and Inhibits Its Activity

The Inhibitory Effect of Phospholemman on the Sodium Pump Requires Its Palmitoylation

Coordinated Regulation of Cardiac Na+/Ca2+ Exchanger and Na+-K+-ATPase by Phospholemman (FXYD1)

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