5JR7

Crystal structure of an ACRDYS heterodimer [RIa(92-365):C] of PKA

Summary for 5JR7

• Entry DOI: 10.2210/pdb5jr7/pdb
• Descriptor: cAMP-dependent protein kinase catalytic subunit alpha, cAMP-dependent protein kinase type I-alpha regulatory subunit, ADENOSINE-5'-DIPHOSPHATE (3 entities in total)
• Functional Keywords: pka signaling, ria subunit, disease mutations, dysfunctional acrdys mutant, transferase-camp binding protein complex, transferase/camp binding protein
• Biological source: Mus musculus (Mouse); More
• Total number of polymer chains: 4
• Total formula weight: 144155.18

Authors

Bruystens, J.G.H.,Wu, J.,Taylor, S.S. (deposition date: 2016-05-05, release date: 2017-03-15, Last modification date: 2024-11-20)

Primary citation

Bruystens, J.G.,Wu, J.,Fortezzo, A.,Del Rio, J.,Nielsen, C.,Blumenthal, D.K.,Rock, R.,Stefan, E.,Taylor, S.S.
Structure of a PKA RI alpha Recurrent Acrodysostosis Mutant Explains Defective cAMP-Dependent Activation.
J. Mol. Biol., 428:4890-4904, 2016

PubMed Abstract: Most disease-related mutations that impair cAMP protein kinase A (PKA) signaling are present within the regulatory (R) PKA RI alpha-subunit (RIα). Although mutations in the PRKAR1A gene are linked to Carney complex (CNC) disease 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 (CNB) 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 catalytic (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. 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 the functional regulation of PKA activity.

PubMed: 27825928
DOI: 10.1016/j.jmb.2016.10.033

Experimental method

X-RAY DIFFRACTION (3.56 Å)