scholarly journals Sequential activation of p38 and ERK pathways by cGMP-dependent protein kinase leading to activation of the platelet integrin αIIbβ3

Blood ◽  
2006 ◽  
Vol 107 (3) ◽  
pp. 965-972 ◽  
Author(s):  
Zhenyu Li ◽  
Guoying Zhang ◽  
Robert Feil ◽  
Jiahuai Han ◽  
Xiaoping Du
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Dominant Negative ◽  
Platelet Glycoprotein ◽  
Dominant Negative Mutant ◽  
Integrin Activation ◽  
Dependent Protein Kinase ◽  
Integrin Αiibβ3 ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

AbstractIntegrin activation (inside-out signaling) in platelets can be initiated by agonists such as von Willebrand factor (VWF) and thrombin. Here we show that a mitogen-activated protein kinase (MAPK), p38, plays an important role in the activation of integrin αIIbβ3 induced by VWF and thrombin. A dominant-negative mutant of p38, p38AF, inhibits αIIbβ3 activation induced by VWF binding to its receptor, the platelet glycoprotein Ib-IX (GPIb-IX), and p38 inhibitors diminish platelet aggregation induced by VWF or low-dose thrombin. The inhibitory effect of p38 inhibitor is unlikely to be caused by the previous suggested effect on cyclo-oxygenase, as inhibition also was observed in the presence of high concentrations of cyclo-oxygenase inhibitor, aspirin. VWF or thrombin induces p38 activation, which is inhibited in cGMP-dependent protein kinase (PKG)-knockout mouse platelets and PKG inhibitor-treated human platelets, indicating that activation of p38 is downstream from PKG in the signaling pathway. p38AF or p38 inhibitors diminish PKG-induced phosphorylation of extracellular stimuli-responsive kinase (ERK), which also is important in integrin activation. Thus, p38 plays an important role in mediating PKG-dependent activation of ERK. These data delineate a novel signaling pathway in which platelet agonists sequentially activate PKG, p38, and ERK pathways leading to integrin activation.

scholarly journals Stimulation of neuronal KATP channels by cGMP-dependent protein kinase: involvement of ROS and 5-hydroxydecanoate-sensitive factors in signal transduction

2010 ◽  
Vol 298 (4) ◽  
pp. C875-C892 ◽  
Author(s):  
Yongping Chai ◽  
Yu-Fung Lin
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Neuronal Excitability ◽  
Single Channel ◽  
Katp Channels ◽  
Membrane Excitability ◽  
Dependent Protein Kinase ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Stimulation Of

The ATP-sensitive potassium (KATP) channel couples intracellular metabolic state to membrane excitability. Recently, we demonstrated that neuronal KATP channels are functionally enhanced by activation of a nitric oxide (NO)/cGMP/cGMP-dependent protein kinase (PKG) signaling cascade. In this study, we further investigated the intracellular mechanism underlying PKG stimulation of neuronal KATP channels. By performing single-channel recordings in transfected HEK293 and neuroblastoma SH-SY5Y cells, we found that the increase of Kir6.2/SUR1 (i.e., the neuronal-type KATP) channel currents by PKG activation in cell-attached patches was diminished by 5-hydroxydecanoate (5-HD), an inhibitor of the putative mitochondrial KATP channel; N-(2-mercaptopropionyl)glycine, a reactive oxygen species (ROS) scavenger, and catalase, a hydrogen peroxide (H2O2)-decomposing enzyme. These reagents also ablated NO-induced KATP channel stimulation and prevented the shifts in the single-channel open- and closed-time distributions resulting from PKG activation and NO induction. Bath application of H2O2 reproduced PKG stimulation of Kir6.2/SUR1 but did not activate tetrameric Kir6.2LRKR368/369/370/371AAAA channels. Moreover, neither the PKG activator nor exogenous H2O2 was able to enhance the function of KATP channels in the presence of Ca2+ chelators and calmodulin antagonists, whereas the stimulatory effect of H2O2 was unaffected by 5-HD. Altogether, in this report we provide novel evidence that activation of PKG stimulates neuronal KATP channels by modulating intrinsic channel gating via a 5-HD-sensitive factor(s)/ROS/Ca2+/calmodulin signaling pathway that requires the presence of the SUR1 subunit. This signaling pathway may contribute to neuroprotection against ischemic injury and regulation of neuronal excitability and neurotransmitter release by modulating the function of neuronal KATP channels.

Antagonizing cAMP-dependent protein kinase A in the dorsal CNS activates a conserved Sonic hedgehog signaling pathway

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2885-2894 ◽  
Author(s):  
D.J. Epstein ◽  
E. Marti ◽  
M.P. Scott ◽  
A.P. McMahon
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Sonic Hedgehog ◽  
Cell Types ◽  
Floor Plate ◽  
Dominant Negative ◽  
Dependent Protein Kinase ◽  
Dependent Protein ◽  
Hh Signaling ◽  
Kinase A

Hedgehog (Hh) signaling plays a significant role in defining the polarity of a variety of tissue types along the anterior/posterior and dorsal/ventral axes in both vertebrate and invertebrate organisms. The pathway through which Hh transduces its signal is still obscure, however, recent data have implicated the cyclic AMP-dependent protein kinase A as a negative regulator of the Hh signal transduction pathway. One of the vertebrate Hh family members, Sonic hedgehog (Shh), can induce ventral neural cell types both in vivo and in vitro; high concentrations induce floor plate and lower concentrations motor neurons. To investigate whether PKA plays an active role in the suppression of ventral neural differentiation, we generated transgenic embryos expressing a dominant negative form of PKA (dnPKA) in primarily dorsal aspects of the mouse CNS. Similar to our earlier results with Shh, we observed the induction of floor plate and motor neuron markers in embryos expressing the dominant negative PKA transgene and the loss of dorsal gene expression at rostral levels. Thus suppression of PKA activity is sufficient to activate targets of the Shh signaling pathway in the vertebrate CNS suggesting that induction of ventral cell types occurs via the antagonistic action of Shh on PKA activity. Two mammalian target genes that are strongly expressed in ectopic dorsal locations in response to dnPKA are Ptc and Gli. As both of these are targets of Drosophila Hh signaling, our data point to an evolutionary conservation in both the mechanisms of signaling and the effectors of the signaling pathway.

Thrombin stimulation of p38 MAP kinase in human platelets is mediated by ADP and thromboxane A2 and inhibited by cGMP/cGMP-dependent protein kinase

Blood ◽  
2006 ◽  
Vol 109 (2) ◽  
pp. 616-618 ◽  
Author(s):  
Antonija Jurak Begonja ◽  
Jörg Geiger ◽  
Natalia Rukoyatkina ◽  
Steffen Rauchfuss ◽  
Stepan Gambaryan ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Thromboxane A2 ◽  
Human Platelets ◽  
P38 Map Kinase ◽  
Integrin Activation ◽  
Dependent Protein Kinase ◽  
Kinase Activation ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

Abstract p38 MAP kinase in human platelets is activated by platelet agonists including thrombin, thromboxane A2 (TxA2), ADP, and others. However, both upstream mechanisms of p38 MAP kinase activation, and their downstream sequelae, are presently controversial and essentially unclear. Certain studies report sequential activation of cGMP-dependent protein kinase (PKG) and p38/ERK pathways by platelet agonists, leading to integrin activation and secretion, whereas others establish an essential role of Src/ERK-mediated TxA2 generation for fibrinogen receptor activation in human platelets. Here, we show that ADP secreted from platelet-dense granules, and subsequent activation of P2Y12 receptors, as well as TxA2 release are important upstream mediators of p38 MAP kinase activation by thrombin. However, p38 MAP kinase activation did not significantly contribute to calcium mobilization, P-selectin expression, αIIbβ3 integrin activation, and aggregation of human platelets in response to thrombin. Finally, PKG activation did not stimulate, but rather inhibited, p38 MAP kinase in human platelets.

cDNA Cloning and Gene Expression of Human Type Iα cGMP-Dependent Protein Kinase

Hypertension ◽  
1996 ◽  
Vol 27 (3) ◽  
pp. 552-557 ◽  
Author(s):  
Naohisa Tamura ◽  
Hiroshi Itoh ◽  
Yoshihiro Ogawa ◽  
Osamu Nakagawa ◽  
Masaki Harada ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Cdna Cloning ◽  
Dependent Protein Kinase ◽  
Human Type ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

scholarly journals The cGMP-Dependent Protein Kinase 2 Contributes to Cone Photoreceptor Degeneration in the Cnga3-Deficient Mouse Model of Achromatopsia

2020 ◽  
Vol 22 (1) ◽  
pp. 52
Author(s):  
Mirja Koch ◽  
Constanze Scheel ◽  
Hongwei Ma ◽  
Fan Yang ◽  
Michael Stadlmeier ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mouse Model ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Cone Photoreceptor ◽  
Photoreceptor Degeneration ◽  
Dependent Protein Kinase ◽  
Genetic Ablation ◽  
Cgmp Dependent Protein Kinase ◽  
Dependent Protein

Mutations in the CNGA3 gene, which encodes the A subunit of the cyclic guanosine monophosphate (cGMP)-gated cation channel in cone photoreceptor outer segments, cause total colour blindness, also referred to as achromatopsia. Cones lacking this channel protein are non-functional, accumulate high levels of the second messenger cGMP and degenerate over time after induction of ER stress. The cell death mechanisms that lead to loss of affected cones are only partially understood. Here, we explored the disease mechanisms in the Cnga3 knockout (KO) mouse model of achromatopsia. We found that another important effector of cGMP, the cGMP-dependent protein kinase 2 (Prkg2) is crucially involved in cGMP cytotoxicity of cones in Cnga3 KO mice. Virus-mediated knockdown or genetic ablation of Prkg2 in Cnga3 KO mice counteracted degeneration and preserved the number of cones. Analysis of markers of endoplasmic reticulum stress and unfolded protein response confirmed that induction of these processes in Cnga3 KO cones also depends on Prkg2. In conclusion, we identified Prkg2 as a novel key mediator of cone photoreceptor degeneration in achromatopsia. Our data suggest that this cGMP mediator could be a novel pharmacological target for future neuroprotective therapies.

scholarly journals Genetic Involvement of a cAMP-Dependent Protein Kinase in a G Protein Signaling Pathway Regulating Morphological and Chemical Transitions in Aspergillus nidulans

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 591-600
Author(s):  
Kiminori Shimizu ◽  
Nancy P Keller
Keyword(s):  
Protein Kinase ◽  
Aspergillus Nidulans ◽  
Signaling Pathway ◽  
G Protein ◽  
Radial Growth ◽  
Morphological Development ◽  
Dependent Protein Kinase ◽  
Α Subunit ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

Abstract In the filamentous fungus Aspergillus nidulans, a heterotrimeric G protein α-subunit and an RGS domain protein, encoded by fadA and flbA, respectively, regulate production of the carcinogenic metabolite sterigmatocystin (ST) and asexual spores (i.e., conidia). We investigated the genetic involvement of the cAMP-dependent protein kinase catalytic subunit (PkaA), a potential downstream target of FadA activity, in ST production and conidiation. Relative to wild type, sporulation was decreased in the pkaA overexpression strain but was not totally absent, as occurs in ΔflbA or fadAG42R (fadA-dominant active) strains. Deletion of pkaA resulted in a hyper-conidiating strain with limited radial growth. This phenotype was epistatic to mutation in flbA or fadA; the double mutants ΔpkaA; ΔflbA and ΔpkaA; fadAG42R recovered sporulation and their radial growth was severely restricted. PkaA overexpression also negatively regulated AflR, the ST biosynthesis-specific transcription factor, both transcriptionally and post-transcriptionally. Deletion of pkaA restored ST production in the ΔflbA background but not in the fadAG42R background. These data provide genetic evidence that the FlbA/FadA signaling pathway regulating ST production and morphological development is partially mediated through PkaA.

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