PKA catalytic subunit mutations in adrenocortical Cushing’s adenoma impair association with the regulatory subunit

Calebiro, Davide; Hannawacker, Annette; Lyga, Sandra; Bathon, Kerstin; Zabel, Ulrike; Ronchi, Cristina L.; Beuschlein, Felix; Reincke, Martín; Lorenz, Kristina; Allolio, Bruno; Kisker, Caroline; Fassnacht, Martin; Lohse, Martin J.

doi:10.1038/ncomms6680

Cited by 65 publications

(82 citation statements)

References 28 publications

(45 reference statements)

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“…However, genetic variants of PDE11A4 contribute only marginally to the development of GH-secreting adenomas (25). Recently, mutations affecting the gene encoding the catalytic subunit a of the PKA (PRKACA) have been reported in a large proportion of cortisol-secreting adrenocortical adenomas (26,27,28,29,30), resulting in an increased PKA activity (31). Nevertheless, no hot spot mutations of PRKACA have been identified in a large cohort of GH-secreting adenomas (32).…”

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confidence: 99%

Landscape of somatic mutations in sporadic GH-secreting pituitary adenomas

Ronchi¹,

Peverelli

Herterich

et al. 2016

European Journal of Endocrinology

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Context: Alterations in the cAMP signaling pathway are common in hormonally active endocrine tumors. Somatic mutations at GNAS are causative in 30-40% of GH-secreting adenomas. Recently, mutations affecting the USP8 and PRKACA gene have been reported in ACTH-secreting pituitary adenomas and cortisol-secreting adrenocortical adenomas respectively. However, the pathogenesis of many GH-secreting adenomas remains unclear. Aim: Comprehensive genetic characterization of sporadic GH-secreting adenomas and identification of new driver mutations. Design: Screening for somatic mutations was performed in 67 GH-secreting adenomas by targeted sequencing for GNAS, PRKACA, and USP8 mutations (nZ31) and next-generation exome sequencing (nZ36). Results: By targeted sequencing, known activating mutations in GNAS were detected in five cases (16.1%), while no somatic mutations were observed in both PRKACA and USP8. Whole-exome sequencing identified 132 protein-altering somatic mutations in 31/36 tumors with a median of three mutations per sample (range: 1-13). The only recurrent mutations have been observed in GNAS (31.4% of cases). However, seven genes involved in cAMP signaling pathway were affected in 14 of 36 samples and eight samples harbored variants in genes involved in the calcium signaling or metabolism. At the enrichment analysis, several altered genes resulted to be associated with developmental processes. No significant correlation between genetic alterations and the clinical data was observed. Conclusion: This study provides a comprehensive analysis of somatic mutations in a large series of GH-secreting adenomas. No novel recurrent genetic alterations have been observed, but the data suggest that beside cAMP pathway, calcium signaling might be involved in the pathogenesis of these tumors.

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confidence: 99%

Landscape of somatic mutations in sporadic GH-secreting pituitary adenomas

Ronchi¹,

Peverelli

Herterich

et al. 2016

European Journal of Endocrinology

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“…Similarly, residues Leu199 and Cys200 are located next to Thr198, which is part of the so-called 'activation loop' and is phosphorylated during the synthesis of the Ca subunit (8,34,51). This region of the C subunit is oriented parallel to the inhibitory sequence of the R subunit.…”

Section: Prkaca Mutationsmentioning

confidence: 99%

“…Indeed, Leu206 is part of the active site cleft of the Ca subunit and participates in forming a hydrophobic pocket (8,51). This hydrophobic pocket is responsible for substrate binding and recognition as well as for the interaction with the inhibitory sequence of the R subunit.…”

Section: Prkaca Mutationsmentioning

confidence: 99%

“…By analyzing the solved X-ray crystal structure of the mouse RIIb-Ca-holoenzyme (37), we predicted that both originally identified mutations might interfere with the association with the R subunit, thus rendering the Ca subunit constitutively active (8,50,51).…”

Section: Prkaca Mutationsmentioning

confidence: 99%

“…This hydrophobic pocket is responsible for substrate binding and recognition as well as for the interaction with the inhibitory sequence of the R subunit. Therefore, we predicted that the substitution of Leu206 with a bulky and positively charged amino acid such as arginine would lead to steric hindrance between the side chain of this amino acid and residues Val115 and Tyr228 of the regulatory subunit (8,51) (Fig. 2).…”

Section: Prkaca Mutationsmentioning

confidence: 99%

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cAMP signaling in cortisol-producing adrenal adenoma

Calebiro

Dalmazi

Bathon

et al. 2015

European Journal of Endocrinology

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The cAMP signaling pathway is one of the major players in the regulation of growth and hormonal secretion in adrenocortical cells. Although its role in the pathogenesis of adrenocortical hyperplasia associated with Cushing's syndrome has been clarified, a clear involvement of the cAMP signaling pathway and of one of its major downstream effectors, the protein kinase A (PKA), in sporadic adrenocortical adenomas remained elusive until recently. During the last year, a report by our group and three additional independent groups showed that somatic mutations of PRKACA, the gene coding for the catalytic subunit a of PKA, are a common genetic alteration in patients with Cushing's syndrome due to adrenal adenomas, occurring in 35-65% of the patients. In vitro studies revealed that those mutations are able to disrupt the association between catalytic and regulatory subunits of PKA, leading to a cAMP-independent activity of the enzyme. Despite somatic PRKACA mutations being a common finding in patients with clinically manifest Cushing's syndrome, the pathogenesis of adrenocortical adenomas associated with subclinical hypercortisolism seems to rely on a different molecular background. In this review, the role of cAMP/PKA signaling in the regulation of adrenocortical cell function and its alterations in cortisolproducing adrenocortical adenomas will be summarized, with particular focus on recent developments.

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Cushing's syndrome mutant PKA^L^205R exhibits altered substrate specificity

et al. 2017

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The PKAL205R hotspot mutation has been implicated in Cushing’s Syndrome through hyperactive gain-of-function PKA signaling, however its influence on substrate specificity has not been investigated. Here, we employ the Proteomic Peptide Library (ProPeL) approach to create high-resolution models for PKAWT and PKAL205R substrate specificity. We reveal that the L205R mutation reduces canonical hydrophobic preference at the substrate P+1 position, and increases acidic preference in downstream positions. Using these models, we designed peptide substrates that exhibit altered selectivity for specific PKA variants, and demonstrate the feasibility of selective PKAL205R loss-of-function signaling. Through these results, we suggest that substrate rewiring may contribute to Cushing’s Syndrome disease etiology, and introduce a powerful new paradigm for investigating mutation-induced kinase substrate rewiring in human disease.

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PKA catalytic subunit mutations in adrenocortical Cushing’s adenoma impair association with the regulatory subunit

Cited by 65 publications

References 28 publications

Landscape of somatic mutations in sporadic GH-secreting pituitary adenomas

Landscape of somatic mutations in sporadic GH-secreting pituitary adenomas

cAMP signaling in cortisol-producing adrenal adenoma

Cushing's syndrome mutant PKA^L^205R exhibits altered substrate specificity

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PKA catalytic subunit mutations in adrenocortical Cushing’s adenoma impair association with the regulatory subunit

Cited by 65 publications

References 28 publications

Landscape of somatic mutations in sporadic GH-secreting pituitary adenomas

Landscape of somatic mutations in sporadic GH-secreting pituitary adenomas

cAMP signaling in cortisol-producing adrenal adenoma

Cushing's syndrome mutant PKAL205R exhibits altered substrate specificity

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Resources

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Cushing's syndrome mutant PKA^L^205R exhibits altered substrate specificity