Cyclic nucleotide content of tobacco BY-2 cells

Richards, Helen; Das, Swadipa; Smith, Christopher J.; Pereira, Louisa; Geisbrecht, Alan; Devitt, Nicola J; Games, David E.; Geyschem, Jan van; Brenton, A.G.; Newton, Russell P.

doi:10.1016/s0031-9422(02)00266-2

Cited by 28 publications

(16 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Nonetheless, cAMP has been unequivocally documented to be present in plant cells (27,40). Adenylyl cyclase activity as well as cAMP phosphodiesterase activity is present in plants (4,27).…”

Section: Discussionmentioning

confidence: 99%

Ca²⁺, cAMP, and transduction of non-self perception during plant immune responses

Qi²,

Smigel³

et al. 2009

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

125

116

View full text Add to dashboard Cite

Ca 2+ influx is an early signal initiating cytosolic immune responses to pathogen perception in plant cells; molecular components linking pathogen recognition to Ca 2+ influx are not delineated. Work presented here provides insights into this biological system of non-self recognition and response activation. We have recently identified a cyclic nucleotide-activated ion channel as facilitating the Ca 2+ flux that initiates immune signaling in the plant cell cytosol. Work in this report shows that elevation of cAMP is a key player in this signaling cascade. We show that cytosolic Ca 2+ elevation, nitric oxide (NO) and reactive oxygen species generation, as well as immune signaling, lead to a hypersensitive response upon application of pathogens and/or conserved molecules that are components of microbes and are all dependent on cAMP generation. Exogenous cAMP leads to Ca 2+ channel-dependent cytosolic Ca 2+ elevation, NO generation, and defense response gene expression in the absence of the non-self pathogen signal. Inoculation of leaves with a bacterial pathogen leads to cAMP elevation coordinated with Ca 2+ rise. cAMP acts as a secondary messenger in plants; however, no specific protein has been heretofore identified as activated by cAMP in a manner associated with a signaling cascade in plants, as we report here. Our linkage of cAMP elevation in pathogen-inoculated plant leaves to Ca 2+ channels and immune signaling downstream from cytosolic Ca 2+ elevation provides a model for how non-self detection can be transduced to initiate the cascade of events in the cell cytosol that orchestrate pathogen defense responses.

show abstract

“…Nonetheless, cAMP has been unequivocally documented to be present in plant cells (27,40). Adenylyl cyclase activity as well as cAMP phosphodiesterase activity is present in plants (4,27).…”

Section: Discussionmentioning

confidence: 99%

Ca²⁺, cAMP, and transduction of non-self perception during plant immune responses

Qi²,

Smigel³

et al. 2009

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

125

116

View full text Add to dashboard Cite

show abstract

“…The lipophilic cAMP analog Bt 2 cAMP was used to activate currents in the whole cell and outside-out patch configurations; cAMP was added to the perfusion bath for studies with inside-out patches. It should be noted that the concentration of cAMP (or Bt 2 cAMP) used in the studies reported here is substantially higher than the ambient level thought to be present in plant cells, although both temporal and spatial spikes in plant cell [cAMP] can occur (8,9,10,26). However, the cAMP level we used is of a similar magnitude as the level of cyclic nucleotide ligand used to activate CNGCs in many patch clamp studies.…”

Section: Methodsmentioning

confidence: 89%

“…However, more recent studies using a cyclic nucleotide fluorosensor (9) injected into pollen tubes have reported cAMP levels as high as ϳ150 nM. Use of tandem mass spectrometry (10) for cyclic nucleotide quantification has confirmed the presence of cAMP (as well as cGMP) in plant cells. Furthermore, a partial clone encoding a protein with homology to fungal adenylate cyclase has been identified in corn pollen; importantly, its translation product was shown to have adenylate cyclase activity (9).…”

mentioning

confidence: 99%

Cyclic Adenosine Monophosphate Regulates Calcium Channels in the Plasma Membrane of Arabidopsis Leaf Guard and Mesophyll Cells

Lemtiri‐Chlieh

Berkowitz

2004

Journal of Biological Chemistry

103

View full text Add to dashboard Cite

The effect of cAMP on Ca 2؉ -permeable channels from Arabidopsis thaliana leaf guard cell and mesophyll cell protoplasts was studied using the patch clamp technique. In the whole cell configuration, dibutyryl cAMP was found to increase a hyperpolarization-activated Ba 2؉ conductance (I Ba ). The increase of I Ba was blocked by the addition of GdCl 3 . In excised outside-out patches, the addition of dibutyryl cAMP consistently activated a channel with particularly fast gating kinetics. Current/ voltage analyses indicated a single channel conductance of ϳ13 picosiemens. In patches where we measured some channel activity prior to cAMP application, the data suggest that cAMP enhances channel activity without affecting the single channel conductance. The cAMP activation of these channels was reversible upon washout. The results obtained with excised patches indicate that the cAMP-activated I Ba seen in the whole cell configuration could be explained by a direct effect of cAMP on the Ca 2؉ channel itself or a close entity to the channel. This work represents the first demonstration using patch clamp analysis of the presence in plant cell membranes of an ion channel directly activated by cAMP.

show abstract

“…The N-terminal region has weak homology to cyclic nucleotide binding domains such as those found in cyclic nucleotide-dependent protein kinases. Both cAMP and cGMP have been detected in plants (35), although neither molecule has an effect on the activity of ACH2-6His. Interestingly, BLAST searches of plant EST data bases reveal that the ACH2 N-terminal region is conserved in all plant TesB-like acyl-CoA thioesterases, indicating that it is a common feature in plants.…”

Section: Discussionmentioning

confidence: 99%

Biochemical and Molecular Characterization of ACH2, an Acyl-CoA Thioesterase from Arabidopsis thaliana

Tilton¹,

Shockey²,

Browse

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

By using computer-based homology searches of the Arabidopsis genome, we identified the gene for ACH2, a putative acyl-CoA thioesterase. With the exception of a unique 129-amino acid N-terminal extension, the ACH2 protein is 17-36% identical to members of a family of acyl-CoA thioesterases that are found in both prokaryotes and eukaryotes. The eukaryotic homologs of ACH2 are peroxisomal acyl-CoA thioesterases that are up-regulated during times of increased fatty acid oxidation, suggesting potential roles in peroxisomal ␤-oxidation. We investigated ACH2 to determine whether it has a similar role in the plant cell. Like its eukaryotic homologs, ACH2 carries a putative type 1 peroxisomal targeting sequence (-SKL COOH ), and maintains all the catalytic residues typical of this family of acyl-CoA thioesterases. Analytical ultracentrifugation of recombinant ACH2-6His shows that it associates as a 196-kDa homotetramer in vitro, a result that is significant in light of the cooperative kinetics demonstrated by ACH2-6His in vitro. The cooperative effects are most pronounced with medium chain acyl-CoAs, where the Hill coefficient is 3.8 for lauroyl-CoA, but decrease for long chain acyl-CoAs, where the Hill coefficient is only 1.9 for oleoyl-CoA. ACH2-6His hydrolyzes both medium and long chain fatty acyl-CoAs but has highest activity toward the long chain unsaturated fatty acyl-CoAs. Maximum rates were found with palmitoleoyl-CoA, which is hydrolyzed at 21 mol/min/mg protein. Additionally, ACH2-6His is insensitive to feedback inhibition by free CoASH levels as high as 100 M. ACH2 is most highly expressed in mature tissues such as young leaves and flowers rather than in germinating seedlings where ␤-oxidation is rapidly proceeding. Taken together, these results suggest that ACH2 activity is not linked to fatty acid oxidation as has been suggested for its eukaryotic homologs, but rather has a unique role in the plant cell.

show abstract

Cyclic nucleotide content of tobacco BY-2 cells

Cited by 28 publications

References 47 publications

Ca²⁺, cAMP, and transduction of non-self perception during plant immune responses

Ca²⁺, cAMP, and transduction of non-self perception during plant immune responses

Cyclic Adenosine Monophosphate Regulates Calcium Channels in the Plasma Membrane of Arabidopsis Leaf Guard and Mesophyll Cells

Biochemical and Molecular Characterization of ACH2, an Acyl-CoA Thioesterase from Arabidopsis thaliana

Contact Info

Product

Resources

About

Cyclic nucleotide content of tobacco BY-2 cells

Cited by 28 publications

References 47 publications

Ca2+, cAMP, and transduction of non-self perception during plant immune responses

Ca2+, cAMP, and transduction of non-self perception during plant immune responses

Cyclic Adenosine Monophosphate Regulates Calcium Channels in the Plasma Membrane of Arabidopsis Leaf Guard and Mesophyll Cells

Biochemical and Molecular Characterization of ACH2, an Acyl-CoA Thioesterase from Arabidopsis thaliana

Contact Info

Product

Resources

About

Ca²⁺, cAMP, and transduction of non-self perception during plant immune responses

Ca²⁺, cAMP, and transduction of non-self perception during plant immune responses