Kinase activity assays measure transfer of phosphate from ATP to a protein or peptide substrate, generating phosphorylated substrate, ADP, or incorporated radiolabeled phosphate as the readout; phosphorylation assays measure site-specific phosphorylation in cells or tissues as a proxy for kinase-pathway activation, inhibition, or substrate regulation. Phosphorylation can be detected by phospho-specific Western blot, immunoprecipitation kinase assay, phospho-immunofluorescence, phospho-flow cytometry, luminescent ADP detection, radiolabeled ATP incorporation, or reporter-based pathway assays, and these readouts can be applied to cancer cells, primary neurons, mouse tumors, organoids, inflammatory macrophages, ferroptosis studies, and mitophagy studies when the kinase target is biologically relevant.
Kinase Activity and Phosphorylation Assays
Measuring kinase catalytic activity and substrate protein phosphorylation levels allows for the dynamic elucidation of the core regulatory mechanisms governing intracellular signal transduction cascades. Biochemical assays quantify the inhibitory potency of compounds against kinase function by monitoring ATP consumption, ADP production, or the levels of phosphorylated substrates. Meanwhile, assays utilizing phospho-specific antibodies provide a direct readout of the activation status of target proteins in response to specific physiological stimuli or pathological conditions. Furthermore, assessing kinase binding affinity and selectivity is crucial for unraveling the dysregulated kinase networks implicated in cancers and autoimmune diseases.
Related Experimental Schemes
Kinase activity assays measure the ability of kinases to transfer phosphate groups from ATP to specific substrates, while phosphorylation assays detect the presence and levels of phosphorylated proteins. Common methods include radiolabeled ATP incorporation (e. g. ,), ADP release detection via bioluminescence (e. g. ,[3]), enzyme-linked immunosorbent assays (ELISA) for phospho-specific epitopes (e. g. ,[6]), and microtiter-based formats for high-throughput screening (e. g. ,[8]). The ADP-Glo assay quantifies kinase activity by measuring ADP produced during phosphorylation using a luciferase-based system. Radiometric assays involve autoradiography or scintillation counting after incorporation of 32P-labeled ATP into substrate proteins. ELISA-based approaches rely on phospho-specific antibodies to detect activated kinases in cell lysates or purified samples.
