Molecular evolution of a-kinase anchoring protein (AKAP)-7: implications in comparative PKA compartmentalization

Johnson, Keven R.; Nicodemus‐Johnson, Jessie; Carnegie, Graeme K.; Danziger, Robert S.

doi:10.1186/1471-2148-12-125

Cited by 19 publications

(17 citation statements)

References 62 publications

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“…There is a clear contrast between this novel interaction described for P-Rex1 and PKA and the classical mechanism of interaction of PKA with AKAPs, which regularly occurs through the N terminus of types I and II regulatory subunits (51). Detailed biochemical, cellular, and structural studies have revealed a plethora of AKAPs that interact with the N terminus of PKA regulatory subunits and provide a mechanistic basis by which type II holoenzymes, in particular, are localized to different subcellular compartments (52)(53)(54)(55). Less information is available for type I PKA, although some AKAPs are dual specific and bind to both RI and RII subunits, whereas a few such as sphingosine kinase-interacting protein (SKIP) and the recently discovered small myristoylated and palmitoylated AKAP are RI-specific (56 -58).…”

Section: P-rex1 Dh-ph Catalytic Module Is Also Inhibited By the C-termentioning

confidence: 99%

Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor

Chávez-Vargas¹,

Adame-García

Cervantes‐Villagrana³

et al. 2016

Journal of Biological Chemistry

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Morphology of migrating cells is regulated by Rho GTPases and fine-tuned by protein interactions and phosphorylation.PKA affects cell migration potentially through spatiotemporal interactions with regulators of Rho GTPases. Here we show that the endogenous regulatory (R) subunit of type I PKA interacts with P-Rex1, a Rac guanine nucleotide exchange factor that integrates chemotactic signals. Type I PKA holoenzyme interacts with P-Rex1 PDZ domains via the CNB B domain of RI␣, which when expressed by itself facilitates endothelial cell migration. P-Rex1 activation localizes PKA to the cell periphery, whereas stimulation of PKA phosphorylates P-Rex1 and prevents its activation in cells responding to SDF-1 (stromal cellderived factor 1). The P-Rex1 DEP 1 domain is phosphorylated at Ser-436, which inhibits the DH-PH catalytic cassette by direct interaction. In addition, the P-Rex1 C terminus is indirectly targeted by PKA, promoting inhibitory interactions independently of the DEP 1 -PDZ 2 region. A P-Rex1 S436A mutant construct shows increased RacGEF activity and prevents the inhibitory effect of forskolin on sphingosine 1-phosphate-dependent endothelial cell migration. Altogether, these results support the idea that P-Rex1 contributes to the spatiotemporal localization of type I PKA, which tightly regulates this guanine exchange factor by a multistep mechanism, initiated by interaction with the PDZ domains of P-Rex1 followed by direct phosphorylation at the first DEP domain and putatively indirect regulation of the C terminus, thus promoting inhibitory intramolecular interactions. This reciprocal regulation between PKA and P-Rex1 might represent a key node of integration by which chemotactic signaling is fine-tuned by PKA.Rho guanine exchange factors (RhoGEFs) 4 are mechanistically linked to fundamental cellular processes, such as migration, adhesion, and morphogenesis. Based on their ability to integrate signaling inputs that result in the activation of Rho GTPases, RhoGEFs indirectly contribute to establish nucleation sites for actin polymerization, thus exerting a tight control on cytoskeleton dynamics (1, 2). RhoGEFs can also play a role as scaffolds of different signaling cascades, thus representing regulatory nodes for spatial and temporal control of signaling (3). These fundamental processes are fine-tuned by phosphorylation of RhoGEFs. However, the complex interplay between RhoGEFs and kinases is not completely understood; relevant examples include RhoGEFs known to be activated or inhibited by phosphorylation, some of them by PKA (4, 5).The ability of PKA to modulate the activity of RhoGEFs might be further facilitated by direct interactions that would also influence the subcellular localization of PKA and its accessibility to specific substrates. The paradigmatic example of this situation is AKAP-Lbc, which is a RhoGEF activated by G 12 -coupled receptors that promotes polymerization of actin filaments downstream of Rho and also interacts with multiple kinases regulating mitogenic inputs (6, 7). AKAP-Lbc ...

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Section: P-rex1 Dh-ph Catalytic Module Is Also Inhibited By the C-termentioning

confidence: 99%

Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor

Chávez-Vargas¹,

Adame-García

Cervantes‐Villagrana³

et al. 2016

Journal of Biological Chemistry

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“…Manner. Long isoforms of AKAP18 encode targeting sequences that direct the anchoring protein to a variety of other subcellular locations (37,44). For example, AKAP18γ and -δ are sequestered at the sarcoplasmic reticulum through protein-protein interactions with SERCA2 calcium reuptake channels, whereas in kidney collecting ducts, AKAP18δ is a component of intracellular vesicles (38,39).…”

Section: Akap18 Long Isoforms Transit To the Nucleus In A Pka-dependentmentioning

confidence: 99%

Single nucleotide polymorphisms alter kinase anchoring and the subcellular targeting of A-kinase anchoring proteins

Smith

Omar

Nygren

et al. 2018

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

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A-kinase anchoring proteins (AKAPs) shape second-messenger signaling responses by constraining protein kinase A (PKA) at precise intracellular locations. A defining feature of AKAPs is a helical region that binds to regulatory subunits (RII) of PKA. Mining patient-derived databases has identified 42 nonsynonymous SNPs in the PKA-anchoring helices of five AKAPs. Solid-phase RII binding assays confirmed that 21 of these amino acid substitutions disrupt PKA anchoring. The most deleterious side-chain modifications are situated toward C-termini of AKAP helices. More extensive analysis was conducted on a valine-to-methionine variant in the PKA-anchoring helix of AKAP18. Molecular modeling indicates that additional density provided by methionine at position 282 in the AKAP18γ isoform deflects the pitch of the helical anchoring surface outward by 6.6°. Fluorescence polarization measurements show that this subtle topological change reduces RII-binding affinity 8.8-fold and impairs cAMP responsive potentiation of L-type Ca2+ currents in situ. Live-cell imaging of AKAP18γ V282M-GFP adducts led to the unexpected discovery that loss of PKA anchoring promotes nuclear accumulation of this polymorphic variant. Targeting proceeds via a mechanism whereby association with the PKA holoenzyme masks a polybasic nuclear localization signal on the anchoring protein. This led to the discovery of AKAP18ε: an exclusively nuclear isoform that lacks a PKA-anchoring helix. Enzyme-mediated proximity-proteomics reveal that compartment-selective variants of AKAP18 associate with distinct binding partners. Thus, naturally occurring PKA-anchoring-defective AKAP variants not only perturb dissemination of local second-messenger responses, but also may influence the intracellular distribution of certain AKAP18 isoforms.

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“…1B) or AKAP18d (encoded by AKAP7 gene [25]) (data not shown). Above-mentioned AKAPs were tested first because its presence in liver was previously reported [26][27][28].…”

Section: The Activation Of Adenosine Receptors Involves Specific Acs mentioning

confidence: 99%

“…1A), and by treatment with antibodies against AKAP79/150 (encoded by AKAP5 gene according to the Human Genome Organization (HUGO) gene nomenclature committee [25]), but not D-AKAP2 (encoded by AKAP10 gene [25]) (Fig. Above-mentioned AKAPs were tested first because its presence in liver was previously reported [26][27][28]. Above-mentioned AKAPs were tested first because its presence in liver was previously reported [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Newly synthesized cAMP is integrated at a membrane protein complex signalosome to ensure receptor response specificity

et al. 2016

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Spatiotemporal regulation of cAMP within the cell is required to achieve receptor-specific responses. The mechanism through which the cell selects a specific response to newly synthesized cAMP is not fully understood. In hepatocyte plasma membranes, we identified two functional and independent cAMP-responsive signaling protein macrocomplexes that produce, use, degrade, and regulate their own nondiffusible (sequestered) cAMP pool to achieve their specific responses. Each complex responds to the stimulation of an adenosine G protein-coupled receptor (Ado-GPCR), bound to either A or A , but not simultaneously to both. Each isoprotein involved in each signaling cascade was identified by measuring changes in cAMP levels after receptor activation, and its participation was confirmed by antibody-mediated inactivation. A -Ado-GPCR selective stimulation activates adenylyl cyclase 6 (AC6), which is bound to AKAP79/150, to synthesize cAMP which is used by two other AKAP79/150-tethered proteins: protein kinase A (PKA) and phosphodiesterase 3A (PDE3A). In contrast, A -Ado-GPCR stimulation activates D-AKAP2-attached AC5 to generate cAMP, which is channeled to two other D-AKAP2-tethered proteins: guanine-nucleotide exchange factor 2 (Epac2) and PDE3B. In both cases, prior activation of PKA or Epac2 with selective cAMP analogs prevents de novo cAMP synthesis. In addition, we show that cAMP does not diffuse between these protein macrocomplexes or 'signalosomes'. Evidence of coimmunoprecipitation and colocalization of some proteins belonging to each signalosome is presented. Each signalosome constitutes a minimal functional signaling unit with its own machinery to synthesize and regulate a sequestered cAMP pool. Thus, each signalosome is devoted to ensure the transmission of a unique and unequivocal message through the cell.

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Molecular evolution of a-kinase anchoring protein (AKAP)-7: implications in comparative PKA compartmentalization

Cited by 19 publications

References 62 publications

Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor

Protein Kinase A (PKA) Type I Interacts with P-Rex1, a Rac Guanine Nucleotide Exchange Factor

Single nucleotide polymorphisms alter kinase anchoring and the subcellular targeting of A-kinase anchoring proteins

Newly synthesized cAMP is integrated at a membrane protein complex signalosome to ensure receptor response specificity

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