A 16 kDa protein substrate for protein kinase C and its phosphorylation upon stimulation of vasopressin receptors in rat aortic myocytes

Boulanger-Saunier, Chantal; Stoclet, Jean‐Claude

doi:10.1016/0006-291x(87)91384-2

Cited by 20 publications

(8 citation statements)

References 18 publications

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“…These results are in contrast to earlier studies, in which PLM has been characterized as the major plasma membrane substrate for PKA and PKC in heart cells (41). In addition, following activation of PKA or PKC, PLM has been identified in the plasma membrane of cardiac (6,41,43), skeletal (55,56), smooth muscle (10), and liver (13) cells, as well as in adrenal tumor cells (57). Top, to identify the plasma membrane, cells were costained with an antibody to the ␣-subunit of the Na ϩ -K ϩ -ATPase.…”

Section: Plm Is Localized To Er In Mdck Cellsmentioning

confidence: 99%

“…PLM is a plasma membrane protein found in cardiac (6,41,43), skeletal (55,56), and smooth muscle (10), liver (13), and adrenal tumor cells (57). Activation of ␣-or ␤-adrenergic receptors in the myocardial sarcolemma results in increased phosphorylation of PLM (23,32,43); activation of ␤-adrenergic or vasopressin receptors in smooth muscle also increases phosphorylation (9,10). In isolated guinea pig heart, administration of the ␤-adrenergic agonist, isoproterenol, results in phosphorylation of PLM, coinciding with an increase in contractility (42).…”

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confidence: 99%

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Cytoplasmic targeting signals mediate delivery of phospholemman to the plasma membrane

Lansbery

Burcea

Mendenhall³

et al. 2006

American Journal of Physiology-Cell Physiology

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Section: Plm Is Localized To Er In Mdck Cellsmentioning

confidence: 99%

mentioning

confidence: 99%

Cytoplasmic targeting signals mediate delivery of phospholemman to the plasma membrane

Lansbery

Burcea

Mendenhall³

et al. 2006

American Journal of Physiology-Cell Physiology

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“…Phospholemman (PLM, FXYD1) is expressed in excitable tissues and is unique among the FXYD proteins in that it contains a cytoplasmic region with consensus phosphorylation sites for kinases that include PKC and PKA (21,30). In fact, PLM was originally identified as the primary sarcolemmal substrate for PKA and PKC phosphorylation in the heart (10,23,24). We have shown (6,15,17,26) that PLM forms an integral part of the cardiac Na-K pump complex and provides the link between kinase activation and pump modulation.…”

mentioning

confidence: 99%

Characterization of the phospholemman knockout mouse heart: depressed left ventricular function with increased Na-K-ATPase activity

Bell¹,

Kennington²,

Fuller³

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

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Dunn MJ, Shattock MJ. Characterization of the phospholemman knockout mouse heart: depressed left ventricular function with increased Na-K-ATPase activity. Am J Physiol Heart Circ Physiol 294: H613-H621, 2008. First published December 7, 2007 doi:10.1152/ajpheart.01332.2007, abundantly expressed in the heart, is the primary cardiac sarcolemmal substrate for PKA and PKC. Evidence supports the hypothesis that PLM is part of the cardiac Na-K pump complex and provides the link between kinase activity and pump modulation. PLM has also been proposed to modulate Na/Ca exchanger activity and may be involved in cell volume regulation. This study characterized the phenotype of the PLM knockout (KO) mouse heart to further our understanding of PLM function in the heart. PLM KO mice were bred on a congenic C57/BL6 background. In vivo conductance catheter measurements exhibited a mildly depressed cardiac contractile function in PLM KO mice, which was exacerbated when hearts were isolated and Langendorff perfused. There were no significant differences in action potential morphology in paced Langendorff-perfused hearts. Depressed contractile function was associated with a mild cardiac hypertrophy in PLM KO mice. Biochemical analysis of crude ventricular homogenates showed a significant increase in Na-K-ATPase activity in PLM KO hearts compared with wild-type controls. SDS-PAGE and Western blot analysis of ventricular homogenates revealed small, nonsignificant changes in Na-K-ATPase subunit expression, with two-dimensional gel (isoelectric focusing, SDS-PAGE) analysis revealing minimal changes in ventricular protein expression, indicating that deletion of PLM was the primary reason for the observed PLM KO phenotype. These studies demonstrate that PLM plays an important role in the contractile function of the normoxic mouse heart. Data are consistent with the hypothesis that PLM modulates Na-K-ATPase activity, indirectly affecting intracellular Ca and hence contractile function. FXYD1; contractile function; intracellular sodium regulation IN EXCITABLE TISSUES, the activity of the plasma membrane Na-K-ATPase is vital for the maintenance of normal electrical activity, ionic homeostasis, cell volume control, and substrate and amino acid transport and for setting cellular Ca load and hence contractility. Interventions that influence Na-K-ATPase activity and/or the transmembrane Na gradient can therefore profoundly affect myocardial function. In essence, the Na-KATPase not only influences a wide range of transmembrane transport processes but also indirectly controls myocardial contractility.It has recently been recognized that the FXYD family of small single transmembrane-spanning proteins are tissue-specific regulators of the Na-K-ATPase (3-5, 28). Phospholemman (PLM, FXYD1) is expressed in excitable tissues and is unique among the FXYD proteins in that it contains a cytoplasmic region with consensus phosphorylation sites for kinases that include PKC and PKA (21, 30). In fact, PLM was originally identified as the primary sarcolemmal ...

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“…2). These data suggest that the 16/17-kDa phosphoprotein identified in smooth muscle plasma membrane preparations [12,13,14] was likely PLM. We found that the CP68 PLM signal correlated with cAMP-, but not cGMP-mediated relaxation (fig.…”

Section: Discussionmentioning

confidence: 86%

“…Its dephosphorylation was inhibited by 10 m M NaF. Boulanger-Saunier et al [13] subsequently found that a phorbol ester (TPA) in vitro and arginine vasopressin in vivo induced phosphorylation of the 16-kDa protein on a second site distinct from the PKA site. In 1989, Sarevic et al [14] found that a 17-kDa membrane phosphoprotein, likely PLM, was phosphorylated by PKA but not by protein kinase G. PLM mRNA has been reported in canine aortic, esophageal and gastric smooth muscle [1].…”

Section: Introductionmentioning

confidence: 99%

Serine 68 Phospholemman Phosphorylation during Forskolin-Induced Swine Carotid Artery Relaxation

Rembold¹,

Ripley²,

Meeks³

et al. 2005

J Vasc Res

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Background: Phospholemman (PLM) is an abundant phosphoprotein in the plasma membrane of cardiac, skeletal and smooth muscle. It is a member of the FXYD family of proteins that bind to and regulate the Na,K-ATPase. Protein kinase A (PKA) is known to phosphorylate PLM on serine 68 (S68), although the functional effect of S68 PLM phosphorylation is unclear. We therefore evaluated S68 PLM phosphorylation in swine carotid arteries. Methods: Two anti-PLM antibodies, one to S68 phosphorylated PLM and one to unphosphorylated PLM, were made to PLM peptides in rabbits and tested with purified PLM and PKA-treated PLM. Swine carotid arteries were mounted isometrically, contracted, relaxed with forskolin and then homogenized. Proteins were separated on SDS gels and the intensity of immunoreactivity to the two PLM antibodies determined on immunoblots. Results: The antipeptide antibody ‘C2’ primarily reacted with unphosphorylated PLM, and the antipeptide antibody ‘CP68’ detected S68 PLM phosphorylation. Histamine stimulation of intact swine carotid artery induced a contraction, increased the CP68 PLM antibody signal and reduced the C2 PLM antibody signal. High extracellular [K⁺] depolarization induced a contraction without altering the C2 or CP68 PLM signal. Forskolin-induced relaxation of histamine or extracellular [K⁺] contracted arteries correlated with an increased CP68 signal. Nitroglycerin-induced relaxation was not associated with changes in the C2 or CP68 PLM signal. Conclusions: These data suggest that a contractile agonist increased S68 PLM phosphorylation. Agents that increase [cAMP], but not agents that increase [cGMP], increased S68 PLM phosphorylation. S68 PLM phosphorylation may be involved in cAMP-dependent regulation of smooth muscle force.

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A 16 kDa protein substrate for protein kinase C and its phosphorylation upon stimulation of vasopressin receptors in rat aortic myocytes

Cited by 20 publications

References 18 publications

Cytoplasmic targeting signals mediate delivery of phospholemman to the plasma membrane

Cytoplasmic targeting signals mediate delivery of phospholemman to the plasma membrane

Characterization of the phospholemman knockout mouse heart: depressed left ventricular function with increased Na-K-ATPase activity

Serine 68 Phospholemman Phosphorylation during Forskolin-Induced Swine Carotid Artery Relaxation

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