Cross-talk from β-Adrenergic Receptors Modulates α2A-Adrenergic Receptor Endocytosis in Sympathetic Neurons via Protein Kinase A and Spinophilin

L-type voltage-gated CaV1.2 channels crucially regulate cardiac muscle contraction. Activation of β-adrenergic receptors (β-AR) augments contraction via protein kinase A (PKA)–induced increase of calcium influx through CaV1.2 channels. To date, the full β-AR cascade has never been heterologously reconstituted. A recent study identified Rad, a CaV1.2 inhibitory protein, as essential for PKA regulation of CaV1.2. We corroborated this finding and reconstituted the complete pathway with agonist activation of β1-AR or β2-AR in Xenopus oocytes. We found, and distinguished between, two distinct pathways of PKA modulation of CaV1.2: Rad dependent (∼80% of total) and Rad independent. The reconstituted system reproduces the known features of β-AR regulation in cardiomyocytes and reveals several aspects: the differential regulation of posttranslationally modified CaV1.2 variants and the distinct features of β1-AR versus β2-AR activity. This system allows for the addressing of central unresolved issues in the β-AR–CaV1.2 cascade and will facilitate the development of therapies for catecholamine-induced cardiac pathologies.

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Protein Kinase A and G Protein-coupled Receptor Kinase Phosphorylation Mediates β-1 Adrenergic Receptor Endocytosis through Different Pathways

Journal of Biological Chemistry ◽

10.1074/jbc.m305675200 ◽

2003 ◽

Vol 278 (37) ◽

pp. 35403-35411 ◽

Cited By ~ 116

Author(s):

Antonio Rapacciuolo ◽

Shayela Suvarna ◽

Liza Barki-Harrington ◽

Louis M. Luttrell ◽

Mei Cong ◽

...

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

G Protein ◽

Adrenergic Receptor ◽

Receptor Kinase ◽

G Protein Coupled Receptor ◽

Receptor Endocytosis ◽

Kinase Phosphorylation ◽

G Protein Coupled ◽

Kinase A

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Cross-Talk between Protein Kinase A and Mitogen-Activated Protein Kinases Signalling in the Adaptive Changes Observed during Morphine Withdrawal in the Heart

Journal of Pharmacology and Experimental Therapeutics ◽

10.1124/jpet.109.154583 ◽

2009 ◽

Vol 330 (3) ◽

pp. 771-782 ◽

Cited By ~ 2

Author(s):

P. Almela ◽

N. M. Atucha ◽

M. V. Milanés ◽

M. L. Laorden

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Protein Kinases ◽

Cross Talk ◽

Morphine Withdrawal ◽

Mitogen Activated Protein Kinases ◽

Adaptive Changes ◽

Mitogen Activated Protein ◽

Kinase A

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Two PKA RIα holoenzyme states define ATP as an isoform-specific orthosteric inhibitor that competes with the allosteric activator, cAMP

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1906036116 ◽

2019 ◽

Vol 116 (33) ◽

pp. 16347-16356 ◽

Cited By ~ 9

Author(s):

Tsan-Wen Lu ◽

Jian Wu ◽

Phillip C. Aoto ◽

Jui-Hung Weng ◽

Lalima G. Ahuja ◽

...

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Cross Talk ◽

Structural Diversity ◽

Dimer Interface ◽

Biochemical Studies ◽

Allosteric Mechanisms ◽

Allosteric Activator ◽

Kinase A ◽

In Cells

Protein kinase A (PKA) holoenzyme, comprised of a cAMP-binding regulatory (R)-subunit dimer and 2 catalytic (C)-subunits, is the master switch for cAMP-mediated signaling. Of the 4 R-subunits (RIα, RIβ, RIIα, RIIβ), RIα is most essential for regulating PKA activity in cells. Our 2 RIα2C2 holoenzyme states, which show different conformations with and without ATP, reveal how ATP/Mg2+ functions as a negative orthosteric modulator. Biochemical studies demonstrate how the removal of ATP primes the holoenzyme for cAMP-mediated activation. The opposing competition between ATP/cAMP is unique to RIα. In RIIβ, ATP serves as a substrate and facilitates cAMP-activation. The isoform-specific RI-holoenzyme dimer interface mediated by N3A–N3A′ motifs defines multidomain cross-talk and an allosteric network that creates competing roles for ATP and cAMP. Comparisons to the RIIβ holoenzyme demonstrate isoform-specific holoenzyme interfaces and highlights distinct allosteric mechanisms for activation in addition to the structural diversity of the isoforms.

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