1. Discovery of a Cushing's syndrome protein kinase A mutant that biases signaling through type I AKAPs.
- Author
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Omar, Mitchell H., Byrne, Dominic P., Shrestha, Safal, Lakey, Tyler M., Kyung-Soon Lee, Lauer, Sophia M., Collins, Kerrie B., Daly, Leonard A., Eyers, Claire E., Baird, Geoffrey S., Shao-En Ong, Kannan, Natarajan, Eyers, Patrick A., and Scott, John D.
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CUSHING'S syndrome , *MUTANT proteins , *MOLECULAR dynamics , *INDIVIDUALIZED medicine , *MEDICAL screening - Abstract
Adrenal Cushing's syndrome is a disease of cortisol hypersecretion often caused by mutations in protein kinase A catalytic subunit (PKAc). Using a personalized medicine screening platform, we discovered a Cushing's driver mutation, PKAc-W196G, in ~20% of patient samples analyzed. Proximity proteomics and photokinetic imaging reveal that PKAcW196G is unexpectedly distinct from other described Cushing's variants, exhibiting retained association with type I regulatory subunits (RI) and their corresponding A kinase anchoring proteins (AKAPs). Molecular dynamics simulations predict that substitution of tryptophan-196 with glycine creates a 653-cubic angstrom cleft between the catalytic core of PKAcW196G and type II regulatory subunits (RII), but only a 395-cubic angstrom cleft with RI. Endocrine measurements show that overexpression of RIa or redistribution of PKAcW196G via AKAP recruitment counteracts stress hormone overproduction. We conclude that a W196G mutation in the kinase catalytic core skews R subunit selectivity and biases AKAP association to drive Cushing's syndrome. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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