PKA regulatory subunits mediate synergy among conserved G-protein-coupled receptor cascades

Stefan, Eduard; Malleshaiah, Mohan; Breton, Billy; Ear, Po Hien; Bachmann, Verena; Beyermann, Michael; Bouvier, Michel; Michnick, Stephen W.

doi:10.1038/ncomms1605

Cited by 39 publications

(52 citation statements)

References 59 publications

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“…It has been reported that Rac1 participates to promote the Raf-MekErk cascade (16,(34)(35)(36). To investigate the role of GTP-Rac1 in Erk1/2 activation, we used HEK293 cells, which show no increase of Erk1/2 phosphorylation in response to Forskolin alone (18). We confirmed observations that exclusively the overexpression of the constitutive active GTP-Rac1 variant activates Erk1/2 (16) (Fig.…”

Section: Pka Rii Subunits Form Protein Complexes With Rac1 In Vitro Asupporting

confidence: 69%

“…These processes are distinct from the mechanism we describe here, where Rac-anchored PKA activities directly contribute to the activation of downstream effectors of GTP-Rac signaling leading to Erk1/2 activation. Another GTPase, which we have identified in the same screen to be a binary interaction partner of PKA RII subunits, is a component of the trimeric G protein complex Gαi, although without AKAP features (18). In contrast to Rac1:PKA, complex formation of RII subunits with Gαi was observed in response to cAMP elevation.…”

Section: Discussionmentioning

confidence: 93%

“…We performed a systematic screen using a "Venus" yellow fluorescent protein (YFP) protein-fragment complementation assay (PCA) in mammalian cells to identify transient protein: protein interactions emanating from PKA R subunits with downstream components of RTK and GPCR cascades (18). We identified interaction of PKA RIIβ with the small Rho family GTPase Rac1 (Fig.…”

Section: Pka Rii Subunits Form Protein Complexes With Rac1 In Vitro Amentioning

confidence: 99%

“…To map the interaction sites on Rac1, we performed a peptide spotting experiment of Rac1b to confirm interaction in vitro and to determine specific amino acids required for RIIβ binding (18). We identified two potential binding sites located at the C terminus of Rac1, in regions distinct from GTPase-activity sites ("switch regions"; Fig.…”

Section: Pka Rii Subunits Form Protein Complexes With Rac1 In Vitro Amentioning

confidence: 99%

“…At different stages of RTK-mediated signal transmission, these pathways interact to regulate proliferation. Cross-talk originates from trimeric G protein switching [at the GPCR level: shown for the β-2 adrenergic receptor (β2AR)], through different mode of actions of cAMP-PKA on G proteins like Ras-related protein 1 (Rap1) and inhibitory G protein alpha i (Gαi) and by modulation of the proto-oncogene Raf1 (13,(17)(18)(19)(20). In addition, scaffolding proteins like AKAP-Lbc, phosphorylation of phosphodiesterases and phosphatases contribute to this cross-talk related to MAPK signaling (21)(22)(23).…”

mentioning

confidence: 99%

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Reciprocal regulation of PKA and Rac signaling

Bachmann

Riml

Huber

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Activated G protein-coupled receptors (GPCRs) and receptor tyrosine kinases relay extracellular signals through spatial and temporal controlled kinase and GTPase entities. These enzymes are coordinated by multifunctional scaffolding proteins for precise intracellular signal processing. The cAMP-dependent protein kinase A (PKA) is the prime example for compartmentalized signal transmission downstream of distinct GPCRs. A-kinase anchoring proteins tether PKA to specific intracellular sites to ensure precision and directionality of PKA phosphorylation events. Here, we show that the Rho-GTPase Rac contains A-kinase anchoring protein properties and forms a dynamic cellular protein complex with PKA. The formation of this transient core complex depends on binary interactions with PKA subunits, cAMP levels and cellular GTP-loading accounting for bidirectional consequences on PKA and Rac downstream signaling. We show that GTP-Rac stabilizes the inactive PKA holoenzyme. However, β-adrenergic receptor-mediated activation of GTP-Rac-bound PKA routes signals to the Raf-Mek-Erk cascade, which is critically implicated in cell proliferation. We describe a further mechanism of how cAMP enhances nuclear Erk1/2 signaling: It emanates from transphosphorylation of p21-activated kinases in their evolutionary conserved kinase-activation loop through GTPRac compartmentalized PKA activities. Sole transphosphorylation of p21-activated kinases is not sufficient to activate Erk1/2. It requires complex formation of both kinases with GTP-Rac1 to unleash cAMP-PKA-boosted activation of Raf-Mek-Erk. Consequently GTPRac functions as a dual kinase-tuning scaffold that favors the PKA holoenzyme and contributes to potentiate Erk1/2 signaling. Our findings offer additional mechanistic insights how β-adrenergic receptor-controlled PKA activities enhance GTP-Rac-mediated activation of nuclear Erk1/2 signaling. signal transduction | cross-talk S ignal transduction cascades coordinate the plethora of extracellular stimuli into biological responses within cells. The specificity of receptor-initiated signaling responses is encoded by spatial and temporal dynamics of downstream signaling networks (1). These networks, initiating from e.g., the G protein-coupled receptor (GPCR) superfamily and receptor tyrosine kinases (RTK), tightly regulate signaling pathways at several critical points via feedback loops and cross-talk among other pathways (2-5). A large number of GPCR signaling cascades uses cAMP as an intracellular second messenger (3, 6). In response to hormone binding to distinct GPCRs, cAMP is produced and binds to its canonical effector, the cAMP-dependent protein kinase A (PKA). cAMP binding to the PKA regulatory subunits (R) induces dissociation of the tetrameric PKA holoenzyme, resulting in active PKA catalytic subunits (PKAc; Fig. 1C) (7, 8). To ensure substrate specificity, PKA is tethered to distinct subcellular compartments through physical interaction with A-kinase anchoring proteins (AKAPs; refs. 9 and 10). It has been long regarded that the...

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Section: Pka Rii Subunits Form Protein Complexes With Rac1 In Vitro Asupporting

confidence: 69%

Section: Discussionmentioning

confidence: 93%

Section: Pka Rii Subunits Form Protein Complexes With Rac1 In Vitro Amentioning

confidence: 99%

Section: Pka Rii Subunits Form Protein Complexes With Rac1 In Vitro Amentioning

confidence: 99%

mentioning

confidence: 99%

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Reciprocal regulation of PKA and Rac signaling

Bachmann

Riml

Huber

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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KinCon: Cell‐based recording of full‐length kinase conformations

et al. 2020

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The spectrum of kinase alterations displays distinct functional characteristics and requires kinase mutation-oriented strategies for therapeutic interference.Besides phosphotransferase activity, protein abundance, and intermolecular interactions, particular patient-mutations promote pathological kinase conformations. Despite major advances in identifying lead molecules targeting clinically relevant oncokinase functions, still many kinases are neglected and not part of drug discovery efforts. One explanation is attributed to challenges in

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The implications of the purinergic signaling throughout pregnancy

Sagrillo-Fagundes

Paim

Pretto

et al. 2021

Journal Cellular Physiology

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Purinergic signaling is a necessary mechanism to trigger or even amplify cell communication. Its ligands, notably adenosine triphosphate (ATP) and adenosine, modulate specific membrane-bound receptors in virtually all human cells. Regardless of the stage of the pregnancy, cellular communication between maternal, placental, and fetal cells is the paramount mechanism to sustain its optimal status. In this review, we describe the crucial role of purinergic signaling on the regulation of the maternal-fetal trophic exchanges, immune control, and endocrine exchanges throughout pregnancy. The nature of the modulation of both ATP and adenosine on the embryo-maternal interface, going through placental invasion until birth delivery depends on the general maternal-fetal health state and consequently on the selective activation of their specific receptors. In addition, an increasing number of studies have been demonstrating the pivotal role of ATP and adenosine in modulating deleterious effects of suboptimal conditions of pregnancy. Here, we discuss the role of purinergic signaling on the balance that coordinates the embryomaternal exchanges and a promising therapeutic venue in the context of pregnancy disorders.

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PKA regulatory subunits mediate synergy among conserved G-protein-coupled receptor cascades

Cited by 39 publications

References 59 publications

Reciprocal regulation of PKA and Rac signaling

Reciprocal regulation of PKA and Rac signaling

KinCon: Cell‐based recording of full‐length kinase conformations

The implications of the purinergic signaling throughout pregnancy

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