Kinetics and inhibition studies of the L205R mutant ofcAMP ‐dependent protein kinase involved in Cushing's syndrome
| Autor: | Keith C. Ellis, Nicole M. Luzi, Charles E. Lyons, Darrell L. Peterson |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
chemistry.chemical_classification Mutation Protein subunit Mutant L205R‐PKA Peptide cAMP‐dependent protein kinase medicine.disease_cause Molecular biology General Biochemistry Genetics and Molecular Biology 3. Good health 03 medical and health sciences 030104 developmental biology chemistry kinetics ACTH‐independent Cushing's syndrome medicine Potency Protein kinase A Overproduction enzyme inhibition Research Articles Research Article Hormone |
| Zdroj: | FEBS Open Bio |
| ISSN: | 2211-5463 |
| Popis: | Overproduction of cortisol by the hypothalamus–pituitary–adrenal hormone system results in the clinical disorder known as Cushing's syndrome. Genomics studies have identified a key mutation (L205R) in the α‐isoform of the catalytic subunit of cAMP‐dependent protein kinase (PKACα) in adrenal adenomas of patients with adrenocorticotropic hormone‐independent Cushing's syndrome. Here, we conducted kinetics and inhibition studies on the L205R‐PKACα mutant. We have found that the L205R mutation affects the kinetics of both Kemptide and ATP as substrates, decreasing the catalytic efficiency (k cat/K M) for each substrate by 12‐fold and 4.5‐fold, respectively. We have also determined the IC 50 and K i for the peptide substrate‐competitive inhibitor PKI(5–24) and the ATP‐competitive inhibitor H89. The L205R mutation had no effect on the potency of H89, but causes a > 250‐fold loss in potency for PKI(5–24). Collectively, these data provide insights for the development of L205R‐PKACα inhibitors as potential therapeutics. |
| Databáze: | OpenAIRE |
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