Fig. 4: PKA-dependent phosphorylation remains compartmentalized in HT-29 but not in HeLa cells at high cAMP levels.
From: PKA compartmentalization links cAMP signaling and autophagy
HT-29 cells expressing AKAR4 constructs targeted to A the outer mitochondrial membrane (OMM-AKAR4), B the endoplasmic reticulum facing the cytosol (ER-AKAR4), and C the plasma membrane (PM-AKAR4). All constructs responded to treatment with FSK 5 µM, while addition of FSK 20 µM combined to IBMX 500 µM did not further affect the FRET ratio, indicating that all sensors were saturated. Averaged traces ± SD of 15 cells in four independent experiments for OMM-AKAR4; 13 cells in four independent experiments for ER-AKAR4 and 4 cells in three independent experiments for PM-AKAR4. D HeLa cells expressing OMM-AKAR4, E ER-AKAR4, and F PM-AKAR4. Only PM-AKAR4 responded to treatment with FSK 5 µM, while all constructs saturated with FSK 20 µM combined to IBMX 500 µM. Averaged traces ± SD of 13 cells in three independent experiments of OMM-AKAR4; 10 cells in three independent experiments of ER-AKAR4, and 10 cells in three independent experiments for PM-AKAR4.
