2. Academic Validation
  3. Functional Characterization of PRKAR1A Mutations Reveals a Unique Molecular Mechanism Causing Acrodysostosis but Multiple Mechanisms Causing Carney Complex

Functional Characterization of PRKAR1A Mutations Reveals a Unique Molecular Mechanism Causing Acrodysostosis but Multiple Mechanisms Causing Carney Complex

  • J Biol Chem. 2015 Nov 13;290(46):27816-28. doi: 10.1074/jbc.M115.656553.
Yara Rhayem 1,  Catherine Le Stunff 2,  Waed Abdel Khalek 3,  Colette Auzan 3,  Jerome Bertherat 4,  Agnès Linglart 5,  Alain Couvineau 6,  Caroline Silve 7,  Eric Clauser 8
Affiliations

Affiliations

  • 1 From the INSERM U970, Université Paris Descartes, Paris Centre de Recherche Cardiovasculaire, 56 Rue Leblanc, 75015 Paris, France, the Service de Biochimie et Génétique Moléculaire and.
  • 2 INSERM U1169, Université Paris Sud, Hôpital Bicêtre, 94270 Le Kremlin Bicêtre, France.
  • 3 From the INSERM U970, Université Paris Descartes, Paris Centre de Recherche Cardiovasculaire, 56 Rue Leblanc, 75015 Paris, France.
  • 4 Service d'Endocrinologie, Hôpital Cochin, Assistance Publique, Hôpitaux de Paris, 75014 Paris, France, the Institut Cochin, INSERM U1060, Université Paris Descartes, 75014 Paris, France.
  • 5 the Service d'Endocrinologie Pédiatrique, Hôpital Bicêtre, Assistance Publique, Hôpitaux de Paris, 94270 Le Kremlin Bicêtre, France, and.
  • 6 UMR 1149 INSERM, Université Paris Diderot, ERL CNRS 8252, Faculté de Médecine Site Bichat, 75018 Paris, France.
  • 7 the Service de Biochimie et Génétique Moléculaire and INSERM U1169, Université Paris Sud, Hôpital Bicêtre, 94270 Le Kremlin Bicêtre, France.
  • 8 From the INSERM U970, Université Paris Descartes, Paris Centre de Recherche Cardiovasculaire, 56 Rue Leblanc, 75015 Paris, France, the Service de Biochimie et Génétique Moléculaire and eric.clauser@inserm.fr.
PMID: 26405036 DOI: 10.1074/jbc.M115.656553
Abstract

The main target of cAMP is PKA, the main regulatory subunit of which (PRKAR1A) presents mutations in two genetic disorders: acrodysostosis and Carney complex. In addition to the initial recurrent mutation (R368X) of the PRKAR1A gene, several missense and nonsense mutations have been observed recently in acrodysostosis with hormonal resistance. These mutations are located in one of the two cAMP-binding domains of the protein, and their functional characterization is presented here. Expression of each of the PRKAR1A mutants results in a reduction of forskolin-induced PKA activation (measured by a reporter assay) and an impaired ability of cAMP to dissociate PRKAR1A from the catalytic PKA subunits by BRET assay. Modeling studies and sensitivity to cAMP analogs specific for domain A (8-piperidinoadenosine 3',5'-cyclic monophosphate) or domain B (8-(6-aminohexyl)aminoadenosine-3',5'-cyclic monophosphate) indicate that the mutations impair cAMP binding locally in the domain containing the mutation. Interestingly, two of these mutations affect Amino acids for which alternative amino acid substitutions have been reported to cause the Carney complex phenotype. To decipher the molecular mechanism through which homologous substitutions can produce such strikingly different clinical phenotypes, we studied these mutations using the same approaches. Interestingly, the Carney mutants also demonstrated resistance to cAMP, but they expressed additional functional defects, including accelerated PRKAR1A protein degradation. These data demonstrate that a cAMP binding defect is the common molecular mechanism for resistance of PKA activation in acrodysosotosis and that several distinct mechanisms lead to constitutive PKA activation in Carney complex.

Keywords

Acrodysostosis; CRE-luciferase; Carney complex; PRKAR1A; bioluminescence resonance energy transfer (BRET); cell signaling; functional genomics; protein kinase A (PKA); site-directed mutagenesis.

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