Snapshots of Heart Cells in Action (IMAGE) University of California - San Diego Caption The fine spatial and temporal resolution in the colors of this visualization of PKA (protein kinase A) activity in neonatal cardiac myocytes was was made possible by a process called fluorescence resonance energy transfer. Credit UCSD Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.