An NMR portrait of functional and dysfunctional allosteric cooperativity in cAMP‐dependent protein kinase A. Issue 8 (26th March 2023)

• Record Type: Journal Article
• Authors: Olivieri, Cristina; Walker, Caitlin; Veliparambil Subrahmanian, Manu; Porcelli, Fernando; Taylor, Susan S.; Bernlohr, David A.; Veglia, Gianluigi
• Is Part Of: FEBS letters. Volume 597:Issue 8(2023)
• Page Start: 1055
• Page End: 1072
• Publication Date: 2023-03-26
• Subjects: allosteric regulation -- conformational entropy -- cooperativity -- NMR -- protein kinases; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1002/1873-3468.14610
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : The cAMP‐dependent protein kinase A (PKA) is the archetypical eukaryotic kinase. The catalytic subunit (PKA‐C) structure is highly conserved among the AGC‐kinase family. PKA‐C is a bilobal enzyme with a dynamic N‐lobe, harbouring the Adenosine‐5′‐triphosphate (ATP) binding site and a more rigid helical C‐lobe. The substrate‐binding groove resides at the interface of the two lobes. A distinct feature of PKA‐C is the positive binding cooperativity between nucleotide and substrate. Several PKA‐C mutations lead to the development of adenocarcinomas, myxomas, and other rare forms of liver tumours. Nuclear magnetic resonance (NMR) spectroscopy shows that these mutations disrupt the allosteric communication between the two lobes, causing a drastic decrease in binding cooperativity. The loss of cooperativity correlates with changes in substrate fidelity and reduced kinase affinity for the endogenous protein kinase inhibitor (PKI). The similarity between PKI and the inhibitory sequence of the kinase regulatory subunits suggests that the overall mechanism of regulation of the kinase may be disrupted. We surmise that a reduced or obliterated cooperativity may constitute a common trait for both orthosteric and allosteric mutations of PKA‐C that may lead to dysregulation and disease. Abstract : Cyclic AMP‐dependent protein kinase A (PKA) is a ubiquitous signalling enzyme mediating vital cellular processes. Mutations or aberrant fusions of the C‐subunit of PKA are linked to rare cancers. NMR reveals that these modifications disrupt the enzyme's internal allosteric network, resulting in a loss of nucleotide/substrate binding cooperativity, which may constitute a common trait for allosteric and orthosteric disease‐driver mutations.