H89 Phosphoproteomics in PKA-Null Cells

Protein phosphorylation plays a crucial role in propagating cellular responses to both internal and external cues. One of the most important kinases responsible for protein phosphorylation is protein kinase A (PKA). N-[2-p-bromocinnamylamino-ethyl]-5-isoquinolinesulphonamide (H89) is often used as a “PKA specific inhibitor” to study the involvement of PKA in signaling pathways. However, evidence from cell-free experiments suggested that H89 can also inhibit other kinases. In this experiment, previously-generated mouse collecting duct cell lines with and without PKA were treated with H89, followed by mass spectrometry-based phosphoproteomics to globally assess changes in phosphorylation.