Key Points
- To examine the phosphorylation and dephosphorylation processes of purified phospholamban and associated phosphatidylinositides.
- Purified phospholamban was isolated from canine cardiac sarcoplasmic reticulum membranes.
- Phosphorylation was achieved using cAMP-dependent protein kinase to measure Pi incorporation levels.
- Phosphorylated phospholipids were analyzed for their identity and incorporation levels.
- Purified phospholamban demonstrated a phosphorylation level of 207 nmol of Pi/mg of protein.
- Phosphatidylinositol 4-monophosphate and phosphatidylinositol 4,5-bisphosphate were the main phosphorylated phospholipids.
- Phosphorylation of phospholipids was inhibited by a heat-stable inhibitor of cAMP-dependent protein kinase.
Structured PICO
PPopulationCanine cardiac sarcoplasmic reticulum membranes (purified phospholamban)
IInterventionPhosphorylation by cAMP-dependent protein kinase and dephosphorylation by phospholamban phosphatase
OOutcomePhosphorylation levels and lipid composition of phospholambansurrogate
This basic science study characterizes the phosphorylation and dephosphorylation of purified phospholamban and its associated phospholipids from canine cardiac sarcoplasmic reticulum.