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Publication Abstract from PubMed

Familial mutations of the protein kinase A (PKA) R1alpha regulatory subunit lead to a generalized predisposition for a wide range of tumors, from pituitary adenomas to pancreatic and liver cancers, commonly referred to as Carney complex (CNC). CNC mutations are known to cause overactivation of PKA, but the molecular mechanisms underlying such kinase overactivity are not fully understood in the context of the canonical cAMP-dependent activation of PKA. Here, we show that oligomerization-induced sequestration of R1alpha from the catalytic subunit of PKA (C) is a viable mechanism of PKA activation that can explain the CNC phenotype. Our investigations focus on comparative analyses at the level of structure, unfolding, aggregation, and kinase inhibition profiles of wild-type (wt) PKA R1alpha, the A211D and G287W CNC mutants, as well as the cognate acrodysostosis type 1 (ACRDYS1) mutations A211T and G287E. The latter exhibit a phenotype opposite to CNC with suboptimal PKA activation compared with wt. Overall, our results show that CNC mutations not only perturb the classical cAMP-dependent allosteric activation pathway of PKA, but also amplify significantly more than the cognate ACRDYS1 mutations nonclassical and previously unappreciated activation pathways, such as oligomerization-induced losses of the PKA R1alpha inhibitory function.

Noncanonical protein kinase A activation by oligomerization of regulatory subunits as revealed by inherited Carney complex mutations.,Jafari N, Del Rio J, Akimoto M, Byun JA, Boulton S, Moleschi K, Alsayyed Y, Swanson P, Huang J, Martinez Pomier K, Lee C, Wu J, Taylor SS, Melacini G Proc Natl Acad Sci U S A. 2021 May 25;118(21). pii: 2024716118. doi:, 10.1073/pnas.2024716118. PMID:34006641^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.