Phospholamban-to-SERCA2 ratio controls the force-frequency relationship

Markus Meyer, Wolfgang F. Bluhm, Huaping He, Steven R. Post, Frank J. Giordano, Wilbur Y.W. Lew, Wolfgang H. Dillmann

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

The force-frequency relationship (FFR) describes the frequency-dependent potentiation of cardiac contractility. The interaction of the sarcoplasmic reticulum Ca2+-adenosinetriphosphatase (SERCA2) with its inhibitory protein phospholamban (PLB) might be involved in the control of the FFR. The FFR was analyzed in two systems in which the PLB-to-SERCA2 ratio was modulated. Adult rabbit cardiac myocytes were transduced with adenovirus encoding for SERCA2, PLB, and β-galactosidase (control). After 3 days, the relative PLB/SERCA2 values were significantly different between groups (SERCA2, 0.5; control, 1.0; PLB, 4.5). SERCA2 overexpression shortened relaxation by 23% relative to control, whereas PLB prolonged relaxation by 39% and reduced contractility by 47% (0.1 Hz). When the stimulation frequency was increased to 1.5 Hz, myocyte contractility was increased by 30% in control myocytes. PLB-overexpressing myocytes showed an augmented positive FFR (+78%), whereas SERCA2-transduced myocytes displayed a negative FFR (-15%). A more negative FFR was also found in papillary muscles from SERCA2 transgenic mice. These findings demonstrate that the ratio of phospholamban to SERCA2 is an important component in the control of the FFR.

Original languageEnglish (US)
Pages (from-to)H779-H785
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume276
Issue number3 45-3
DOIs
StatePublished - Mar 1999
Externally publishedYes

Keywords

  • Adenovirus
  • Contractility
  • Sarcoplasmic reticulum
  • Sarcoplasmic reticulum calcium-adenosinetriphosphatase
  • Staircase

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