Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart

Phosphorylation site-specific antibodies, quantification of <sup>32</sup>P incorporation into phospholamban, and simultaneous measurements of mechanical activity were used in Langendorff-perfused rat hearts to provide further insights into the underlying mechanisms of phospholamban phosp...

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Autores principales: Mundiña-Weilenmann, Cecilia, Vittone, Leticia Beatriz, Ortale, Manuel, Chiappe de Cingolani, Gladys Ethel, Mattiazzi, Alicia Ramona
Formato: Articulo
Lenguaje:Inglés
Publicado: 1996
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/123153
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id I19-R120-10915-123153
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Medicina
Biología
Rats
Phosphorylation
Heart
Phospholamban
Isoproterenol
spellingShingle Medicina
Biología
Rats
Phosphorylation
Heart
Phospholamban
Isoproterenol
Mundiña-Weilenmann, Cecilia
Vittone, Leticia Beatriz
Ortale, Manuel
Chiappe de Cingolani, Gladys Ethel
Mattiazzi, Alicia Ramona
Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
topic_facet Medicina
Biología
Rats
Phosphorylation
Heart
Phospholamban
Isoproterenol
description Phosphorylation site-specific antibodies, quantification of <sup>32</sup>P incorporation into phospholamban, and simultaneous measurements of mechanical activity were used in Langendorff-perfused rat hearts to provide further insights into the underlying mechanisms of phospholamban phosphorylation. Immunological detection of phospholamban phosphorylation sites showed that the isoproterenol concentration-dependent increase in phospholamban phosphorylation was due to increases in phosphorylation of both Ser<sup>16</sup> and Thr<sup>17</sup> residues. When isoproterenol concentration was increased at extremely low Ca²⁺ supply to the myocardium, phosphorylation of Thr<sup>17</sup> was virtually absent. Under these conditions, <sup>32</sup>P incorporation into phospholamban, due to Ser<sup>16</sup>, decreased by 50%. Changes in Ca²⁺ supply to the myocardium either at constant β-adrenergic stimulation or in the presence of okadaic acid, a phosphatase inhibitor, exclusively modified Thr<sup>17</sup> phosphorylation. Changes in phospholamban phosphorylation due to either Ser<sup>16</sup> and/or Thr<sup>17</sup> were paralleled by changes in myocardial relaxation. The results indicate that cAMP- (Ser<sup>16</sup>) and Ca²⁺-calmodulin (Thr<sup>17</sup>)-dependent pathways of phospholamban phosphorylation can occur independently of each other. However, in the absence of β-adrenergic stimulation, phosphorylation of Thr<sup>17</sup> could only be detected after simultaneous activation of Ca²⁺-calmodulin-dependent protein kinase and inactivation of phosphatase. It is suggested that under physiological conditions, this requisite is only filled by cAMP-dependent mechanisms.
format Articulo
Articulo
author Mundiña-Weilenmann, Cecilia
Vittone, Leticia Beatriz
Ortale, Manuel
Chiappe de Cingolani, Gladys Ethel
Mattiazzi, Alicia Ramona
author_facet Mundiña-Weilenmann, Cecilia
Vittone, Leticia Beatriz
Ortale, Manuel
Chiappe de Cingolani, Gladys Ethel
Mattiazzi, Alicia Ramona
author_sort Mundiña-Weilenmann, Cecilia
title Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
title_short Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
title_full Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
title_fullStr Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
title_full_unstemmed Immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
title_sort immunodetection of phosphorylation sites gives new insights into the mechanisms underlying phospholamban phosphorylation in the intact heart
publishDate 1996
url http://sedici.unlp.edu.ar/handle/10915/123153
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