scholarly journals AaPKAc Regulates Differentiation of Infection Structures Induced by Physicochemical Signals From Pear Fruit Cuticular Wax, Secondary Metabolism, and Pathogenicity of Alternaria alternata

2021 ◽  
Vol 12 ◽  
Author(s):  
Miao Zhang ◽  
Yongcai Li ◽  
Tiaolan Wang ◽  
Yang Bi ◽  
Rong Li ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mutant Strain ◽  
Alternaria Alternata ◽  
Intracellular Camp ◽  
Pear Fruit ◽  
Appressorium Formation ◽  
Dependent Protein Kinase ◽  
Camp Content ◽  
Infection Structures ◽  
Dependent Protein

Alternaria alternata, the casual agent of black rot of pear fruit, can sense and respond to the physicochemical cues from the host surface and form infection structures during infection. To evaluate the role of cyclic AMP-dependent protein kinase (cAMP-PKA) signaling in surface sensing of A. alternata, we isolated and functionally characterized the cyclic adenosine monophosphate-dependent protein kinase A catalytic subunit gene (AaPKAc). Gene expression results showed that AaPKAc was strongly expressed during the early stages of appressorium formation on hydrophobic surfaces. Knockout mutants ΔAaPKAc were generated by replacing the target genes via homologous recombination events. We found that intracellular cAMP content increased but PKA content decreased in ΔAaPKAc mutant strain. Appressorium formation and infection hyphae were reduced in the ΔAaPKAc mutant strain, and the ability of the ΔAaPKAc mutant strain to recognize and respond to high hydrophobicity surfaces and different surface waxes was lower than in the wild type (WT) strain. In comparison with the WT strain, the appressorium formation rate of the ΔAaPKAc mutant strain on high hydrophobicity and fruit wax extract surface was reduced by 31.6 and 49.3% 4 h after incubation, respectively. In addition, AaPKAc is required for the hypha growth, biomass, pathogenicity, and toxin production of A. alternata. However, AaPKAc negatively regulated conidia formation, melanin production, and osmotic stress resistance. Collectively, AaPKAc is required for pre-penetration, developmental, physiological, and pathological processes in A. alternata.

Effects of cAMP on serotonin evoked calcium transients in cultured rat airway smooth muscle cells

1997 ◽  
Vol 272 (5) ◽  
pp. L865-L871 ◽  
Author(s):  
B. Tolloczko ◽  
Y. L. Jia ◽  
J. G. Martin
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Airway Smooth Muscle ◽  
Airway Smooth Muscle Cells ◽  
Intracellular Camp ◽  
Dependent Protein Kinase ◽  
Cyclic Monophosphate ◽  
Dependent Protein ◽  
High Concentrations

Agents increasing intracellular adenosine 3',5'-cyclic monophosphate (cAMP) cause relaxation of airway smooth muscle. However, the mechanisms of their action are not fully understood. We investigated the role of cAMP in the modulation of intracellular Ca2+ concentration ([Ca2+]i) transients evoked by serotonin (5-HT) in cultured rat tracheal smooth muscle (TSM) cells. Forskolin (10(-7) M) caused a significant elevation of intracellular cAMP and a 60% relaxation of tracheal rings contracted with 5-HT but did not affect [Ca2+]i in TSM cells. Forskolin (10(-5) M) completely relaxed tracheal rings and significantly decreased [Ca2+]i during the sustained phase of the 5-HT response. Forskolin-induced relaxation was attenuated by the cAMP-dependent protein kinase A (PKA) inhibitor Rp diastereomer of cAMP (Rp-cAMPS; 10(-4) M) and by the guanosine 3',5'-cyclic monophosphate (cGMP)-dependent protein kinase (PKG) inhibitor [Rp isomer of 8-(4-chlorophenylthio)-guanosine 3',5'-cyclic monophosphorothioate, 10(-4) M]. The effects of forskolin on [Ca2+]i were not altered by the PKA inhibitor but were abolished by the PKG inhibitor and thapsigargin. These results indicate that, in rat TSM, the relaxant effects of high concentrations of cAMP may be mediated, at least in part, by facilitating the sequestration of Ca2+ into intracellular stores by a mechanism involving PKG.

Biochemical changes accompanying enhanced cardiac contractility by ionophore A23187

1985 ◽  
Vol 249 (6) ◽  
pp. H1204-H1210 ◽  
Author(s):  
J. J. Murray ◽  
P. W. Reed ◽  
J. G. Dobson
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Ionophore A23187 ◽  
Phosphorylase Activity ◽  
Dependent Protein Kinase ◽  
Camp Content ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

We have reported that the divalent cation ionophore A23187, like the beta-adrenergic agonist isoproterenol, increased the force of contraction and rate of relaxation and shortened the duration of contraction of papillary muscles isolated from guinea pigs. A23187 produced a fall in resting tension and decreased the contracture tension of K +/- depolarized muscles, as did isoproterenol. In the present studies, isoproterenol produced a concentration-dependent, rapid, and sustained increase in the cyclic AMP (cAMP) content of papillary muscle. In contrast, A23187 had no detectable effect on cAMP levels, even in the presence of the phosphodiesterase inhibitor, papaverine. Neither drug, at concentrations maximal for contractile effects, altered cyclic GMP (cGMP). Isoproterenol increased the cAMP-dependent protein kinase activity ratio, whereas A23187 did not change the activity of this enzyme. However, both A23187 and isoproterenol produced a concentration-dependent increase in phosphorylase activity. Concentrations of A23187 or isoproterenol that enhanced contractility maximally increased the alkali-labile phosphate (by ca. 35%) but were without effect on the acid-labile, alkali-stable phosphate in the total acid precipitable protein. Contractile effects of isoproterenol, which reflect activated Ca2+ uptake, and the increase in phosphorylase activity produced by this agent are believed to be due to an increase in cAMP with subsequent activation of cAMP-dependent protein kinases and phosphorylation of proteins. A23187 may produce similar contractile effects without an increase in cAMP or cAMP-dependent protein kinase activity by activating other protein kinases and/or inhibiting phosphoprotein phosphatases, most likely by its effects on intracellular calcium.

scholarly journals Movement of the free catalytic subunit of cAMP-dependent protein kinase into and out of the nucleus can be explained by diffusion.

1993 ◽  
Vol 4 (10) ◽  
pp. 993-1002 ◽  
Author(s):  
A T Harootunian ◽  
S R Adams ◽  
W Wen ◽  
J L Meinkoth ◽  
S S Taylor ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nuclear Translocation ◽  
Nuclear Accumulation ◽  
Intracellular Camp ◽  
Dependent Protein Kinase ◽  
Regulatory Subunits ◽  
Camp Dependent Protein Kinase ◽  
Block Movement ◽  
C Subunit ◽  
Dependent Protein

The catalytic (C) subunit of cyclic AMP (cAMP) dependent protein kinase (PKA) has previously been shown to enter and exit the nucleus of cells when intracellular cAMP is raised and lowered, respectively. To determine the mechanism of nuclear translocation, fluorescently labeled C subunit was injected into living REF52 fibroblasts either as free C subunit or in the form of holoenzyme (PKA) in which the catalytic and regulatory subunits were labeled with fluorescein and rhodamine, respectively. Quantification of nuclear and cytoplasmic fluorescence intensities revealed that free C subunit nuclear accumulation was most similar to that of macromolecules that diffuse into the nucleus. A glutathione S-transferase-C subunit fusion protein did not enter the nucleus following cytoplasmic microinjection. Puncturing the nuclear membrane did not decrease the nuclear concentration of C subunit, and C subunit entry into the nucleus did not appear to be saturable. Cooling or depleting cells of energy failed to block movement of C subunit into the nucleus. Photobleaching experiments showed that even after reaching equilibrium at high [cAMP], individual molecules of C subunit continued to leave the nucleus at approximately the same rate that they had originally entered. These results indicate that diffusion is sufficient to explain most aspects of C subunit subcellular localization.

Sites of action of protein kinase C on secretory activity in rat parietal cells

1989 ◽  
Vol 256 (1) ◽  
pp. G129-G138 ◽  
Author(s):  
J. F. Hatt ◽  
P. J. Hanson
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Secretory Activity ◽  
Parietal Cells ◽  
Dependent Protein Kinase ◽  
Camp Content ◽  
Kinase C ◽  
Dependent Protein ◽  
Sites Of Action ◽  
Dose Dependent

Sites at which the calcium-sensitive phospholipid-dependent protein kinase, protein kinase C, may influence acid secretion have been investigated in rat isolated parietal cells. In both crude and enriched preparations of parietal cells incubated in a medium containing 100 mM K+, the activators of protein kinase C, 12-O-tetradecanoylphorbol 13-acetate (TPA) and 1-oleoyl-2-acetyl-glycerol (OAG), produced a dose-dependent stimulation [half-maximally effective concentration (EC50) values of 1 nM and 70 microM, respectively] of aminopyrine accumulation, an index of the sequestration of acid in the cell. In a medium containing 4.5 mM K+, and with no added secretagogues, TPA and OAG did not affect aminopyrine accumulation. Histamine-stimulated aminopyrine accumulation was inhibited by TPA [half-maximally effective inhibitory concentration (IC50) of 2.9 nM]. TPA reduced the histamine-stimulation of the adenosine 3',5'-cyclic monophosphate (cAMP) content of parietal cells (47% inhibition at 100 nM TPA) but also inhibited aminopyrine accumulation at or distal to cAMP-dependent protein kinase. Activators of protein kinase C can produce multiple effects on secretory activity in the rat parietal cell.

scholarly journals Regulation of jun-B expression by a cyclic AMP (cAMP)-dependent mechanism in human myeloid cells

Blood ◽  
1991 ◽  
Vol 78 (1) ◽  
pp. 83-88 ◽  
Author(s):  
R Datta ◽  
T Nakamura ◽  
ML Sherman ◽  
D Kufe
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Myeloid Leukemia ◽  
Leukemia Cells ◽  
Intracellular Camp ◽  
Dependent Protein Kinase ◽  
Cyclic Monophosphate ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Jun B

Abstract The present studies have examined the regulation of the jun-B early response gene by cyclic AMP (cAMP)-dependent signaling pathways. The 2.0-kb jun-B transcript was at low but detectable levels in uninduced human HL-60 myeloid leukemia cells. In contrast, treatment with 1 mmol/L8-bromo-adenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) in the presence of isobutylmethylxanthine, an inhibitor of cAMP-dependent phosphodiesterase, was associated with increases in jun-B transcripts that were maximal by 1 hour and then decreased to near pretreatment levels by 6 hours. Similar findings were obtained with 8–(4- chlorophenylthio)-adenosine 3′,5′-cyclic monophosphate (8-CPT-cAMP) and N6,2′–0-dibutyryladenosine 3′,5′-cyclic monophosphate (dBt-cAMP). jun-B transcripts were also increased with other agents that increase intracellular cAMP levels, such as prostaglandin E2 (PGE2) and forskolin. Moreover, inhibition of cAMP-dependent protein kinase by the isoquinolinesulfonamide H-8 blocked 8-Br-cAMP-induced increases in jun- B expression. The results of nuclear run-on assays demonstrate that treatment of HL-60 cells with PGE2, forskolin, 8-Br-cAMP, and dBt-cAMP is associated with increases in the rate of jun-B transcription. The present findings also demonstrate that the related jun-D gene is similarly regulated by a cAMP-dependent pathway. Taken together, these findings suggest that stimulation of cAMP-dependent protein kinase is involved in the induction of jun gene expression in myeloid leukemia cells.

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