Cushing’s Syndrome mutant PKAL205R exhibits altered substrate specificity

Joshua M Lubner, Kimberly L Dodge-Kafka, Cathrine R Carlson, George M Church, Michael F Chou, Daniel Schwartz
This article is a preprint and has not been peer-reviewed.



The PKAL205R hotspot mutation has been implicated in Cushing’s Syndrome through hyperactive gain-of-function PKA signaling, however its influence on substrate specificity has not been investigated.

Here, we employ the Proteomic Peptide Library (ProPeL) approach to create high-resolution models for PKAWT and PKAL205R substrate specificity. We reveal that the L205R mutation reduces canonical hydrophobic preference at the substrate P+1 position, and increases acidic preference in downstream positions. Using these models, we designed peptide substrates that exhibit altered selectivity for specific PKA variants, and demonstrate the feasibility of selective PKAL205R loss-of-function signaling.

Through these results, we suggest that substrate rewiring may contribute to Cushing’s Syndrome disease etiology, and introduce a powerful new paradigm for investigating mutation-induced kinase substrate rewiring in human disease.

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