Key Points
- This research aims to examine how protein kinase C influences calcium uptake in cardiac cells by phosphorylating phospholamban.
- Used a canine cardiac sarcoplasmic reticulum preparation to study protein phosphorylation.
- Compared effects of three different kinases on phospholamban phosphorylation through two-dimensional peptide mapping.
- Phosphorylation of phospholamban by protein kinase C doubled Ca2+ uptake by the sarcoplasmic reticulum.
- All three protein kinases phosphorylated a common peptide in phospholamban, indicating shared regulatory mechanisms.
- Distinct phosphorylation patterns were observed for each kinase on peptide maps.
Structured PICO
PPopulationCanine cardiac sarcoplasmic reticulum preparation
IInterventionCa2+-activated, phospholipid-dependent protein kinase (protein kinase C)
CComparatorEndogenous calmodulin-dependent protein kinase or catalytic subunit of cAMP-dependent protein kinase
OOutcomePhosphorylation of phospholamban and stimulation of Ca2+ uptakesurrogate
Protein kinase C phosphorylates phospholamban and stimulates calcium uptake in cardiac sarcoplasmic reticulum, suggesting a regulatory role similar to cAMP- and calmodulin-dependent kinases.