Structure of a PKA RIα Recurrent Acrodysostosis Mutant Explains Defective cAMP-Dependent Activation
- Univ. of California at San Diego, La Jolla, CA (United States)
- Univ. of Utah, Salt Lake City, UT (United States)
- Univ. of Innsbruck, Innsbruck (Austria)
Most disease related mutations that impair PKA signaling are present within the regulatory PKA RI alpha-subunit (RIα). Although mutations in the PRKAR1A gene are linked to Carney complex disease (CNC) and more recently to acrodysostosis-1 (ACRDYS1), the two diseases show contrasting phenotypes. While CNC mutations cause increased PKA activity, ACRDYS1 mutations result in decreased PKA activity and cAMP resistant holoenzymes. Mapping the ACRDYS1 disease mutations reveals their localization to the second of two tandem cAMP binding domains (CNB-B) and here we characterize a recurrent deletion mutant where the last 14 residues are missing. The crystal structure of a monomeric form of this mutant (RIα92-365) bound to the C subunit reveals the dysfunctional regions of the RIα-subunit. Beyond the missing residues, the entire capping motif is disordered (residues 357-379) and explains the disrupted cAMP binding. Moreover, the effects of the mutation extend far beyond the CNB-B domain and include the active site and N-lobe of the C-subunit, which is in a partially open conformation with the C-tail disordered. A key residue that contributes to this crosstalk, D267, is altered in our structure and we confirmed its functional importance by mutagenesis. In particular, the D267 interaction with Arg241, a residue shown earlier to be important for allosteric regulation, is disrupted thereby strengthening the interaction of D267 with the C-subunit residue Arg194 at the R:C interface. Here, we see here how the switch between active (cAMP-bound) and inactive (holoenzyme) conformations is perturbed and how the dynamically controlled crosstalk between the helical domains of the two CNB-domains is necessary for functional regulation of PKA activity.
- Research Organization:
- Univ. of Utah, Salt Lake City, UT (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- FG02-05ER64026; AC02-05CH11231
- OSTI ID:
- 1422048
- Alternate ID(s):
- OSTI ID: 1410896
- Journal Information:
- Journal of Molecular Biology, Vol. 428, Issue PB; ISSN 0022-2836
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Switching of the folding-energy landscape governs the allosteric activation of protein kinase A
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journal | July 2018 |
Cardiac function modulation depends on the A‐kinase anchoring protein complex
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journal | August 2019 |
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