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Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation.

Freire PP, Alves CA, Deus AF, Leopoldo AP, Leopoldo AS, Silva DC, Tomasi LC, Campos DH, Cicogna AC - Arq. Bras. Cardiol. (2014)

Bottom Line: In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation.Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16.Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.

ABSTRACT

Background: The activation of the beta-adrenergic system promotes G protein stimulation that, via cyclic adenosine monophosphate (cAMP), alters the structure of protein kinase A (PKA) and leads to phospholamban (PLB) phosphorylation. This protein participates in the system that controls intracellular calcium in muscle cells, and it is the primary regulator of sarcoplasmic reticulum calcium pump activity. In obesity, the beta-adrenergic system is activated by the influence of increased leptin, therefore, resulting in higher myocardial phospholamban phosphorylation via cAMP-PKA.

Objective: To investigate the involvement of proteins which regulate the degree of PLB phosphorylation due to beta-adrenergic activation in obesity. In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation.

Methods: Male Wistar rats were randomly distributed into two groups: control (n = 14), fed with normocaloric diet; and obese (n = 13), fed with a cycle of four unsaturated high-fat diets. Obesity was determined by the adiposity index, and protein expressions of phosphatase 1 (PP-1), PKA, PLB, phosphorylated phospholamban at serine16 (PPLB-Ser16) were assessed by Western blot.

Results: Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16.

Conclusion: Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.

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Related in: MedlinePlus

The activation of the beta-adrenergic system, by means of the beta receptor,leads to the stimulation of the G protein, via alpha subunit, thusactivating AC and promoting the transformation of ATP into cAMP. The latteralters the conformation of PKA, releasing and stimulating the PKA catalyticsubunit, which triggers the phosphorylation of different proteins involvedin calcium transport. AC: adenyl cyclase; cAMP: 3’. 5’ cyclic adenosinemonophosphate; ATP: adenosine triphosphate; PKA: protein kinase A.
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f01: The activation of the beta-adrenergic system, by means of the beta receptor,leads to the stimulation of the G protein, via alpha subunit, thusactivating AC and promoting the transformation of ATP into cAMP. The latteralters the conformation of PKA, releasing and stimulating the PKA catalyticsubunit, which triggers the phosphorylation of different proteins involvedin calcium transport. AC: adenyl cyclase; cAMP: 3’. 5’ cyclic adenosinemonophosphate; ATP: adenosine triphosphate; PKA: protein kinase A.

Mentions: The beta-adrenergic system (BAS) modulates cardiac performance via beta receptor, Gprotein, adenylyl cyclase, and cyclic adenosine monophosphate (cAMP). The cAMPalters protein kinase A (PKA), thus releasing the catalytic subunit and activatingthe phosphorylation of myocardial proteins1,2, which are involvedin calcium (Ca2+) transport - Figure1.


Obesity does not lead to imbalance between myocardial phospholamban phosphorylation and dephosphorylation.

Freire PP, Alves CA, Deus AF, Leopoldo AP, Leopoldo AS, Silva DC, Tomasi LC, Campos DH, Cicogna AC - Arq. Bras. Cardiol. (2014)

The activation of the beta-adrenergic system, by means of the beta receptor,leads to the stimulation of the G protein, via alpha subunit, thusactivating AC and promoting the transformation of ATP into cAMP. The latteralters the conformation of PKA, releasing and stimulating the PKA catalyticsubunit, which triggers the phosphorylation of different proteins involvedin calcium transport. AC: adenyl cyclase; cAMP: 3’. 5’ cyclic adenosinemonophosphate; ATP: adenosine triphosphate; PKA: protein kinase A.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126760&req=5

f01: The activation of the beta-adrenergic system, by means of the beta receptor,leads to the stimulation of the G protein, via alpha subunit, thusactivating AC and promoting the transformation of ATP into cAMP. The latteralters the conformation of PKA, releasing and stimulating the PKA catalyticsubunit, which triggers the phosphorylation of different proteins involvedin calcium transport. AC: adenyl cyclase; cAMP: 3’. 5’ cyclic adenosinemonophosphate; ATP: adenosine triphosphate; PKA: protein kinase A.
Mentions: The beta-adrenergic system (BAS) modulates cardiac performance via beta receptor, Gprotein, adenylyl cyclase, and cyclic adenosine monophosphate (cAMP). The cAMPalters protein kinase A (PKA), thus releasing the catalytic subunit and activatingthe phosphorylation of myocardial proteins1,2, which are involvedin calcium (Ca2+) transport - Figure1.

Bottom Line: In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation.Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16.Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brazil.

ABSTRACT

Background: The activation of the beta-adrenergic system promotes G protein stimulation that, via cyclic adenosine monophosphate (cAMP), alters the structure of protein kinase A (PKA) and leads to phospholamban (PLB) phosphorylation. This protein participates in the system that controls intracellular calcium in muscle cells, and it is the primary regulator of sarcoplasmic reticulum calcium pump activity. In obesity, the beta-adrenergic system is activated by the influence of increased leptin, therefore, resulting in higher myocardial phospholamban phosphorylation via cAMP-PKA.

Objective: To investigate the involvement of proteins which regulate the degree of PLB phosphorylation due to beta-adrenergic activation in obesity. In the present study, we hypothesized that there is an imbalance between phospholamban phosphorylation and dephosphorylation, with prevalence of protein phosphorylation.

Methods: Male Wistar rats were randomly distributed into two groups: control (n = 14), fed with normocaloric diet; and obese (n = 13), fed with a cycle of four unsaturated high-fat diets. Obesity was determined by the adiposity index, and protein expressions of phosphatase 1 (PP-1), PKA, PLB, phosphorylated phospholamban at serine16 (PPLB-Ser16) were assessed by Western blot.

Results: Obesity caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, hyperleptinemia and did not alter the protein expression of PKA, PP-1, PLB, PPLB-Ser16.

Conclusion: Obesity does not promote an imbalance between myocardial PLB phosphorylation and dephosphorylation via beta-adrenergic system.

Show MeSH
Related in: MedlinePlus