The cyclic nucleotide phosphodiesterases of spinach chloroplasts and microsomes

Brown, Eric G.; Edwards, Marc B.; Newton, Russell P.; Smith, Christopher J.

doi:10.1016/0031-9422(80)85007-2

Cited by 34 publications

(12 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…cNMP phosphodiesterase enzymatic activity is present in plant cells (22,26,30) and acts to catabolize cAMP and maintain homeostatic levels in the cytosol after changes that occur in the level of this secondary messenger during signaling cascades (4). We hypothesized that blocking the breakdown of endogenous cAMP by inhibition of cNMP phosphodiesterase activity could therefore affect NO generation in the plant cell.…”

Section: Cnmp Cngcs and Immune Signalingmentioning

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

Section: Cnmp Cngcs and Immune Signalingmentioning

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

“…Intriguingly, characteristics of the second class of plant cyclic nucleotide phosphodiesterases suggest a function in RNA degradation, which was first proposed by Lin and Varner (1972). Therefore, it is not surprising that tomato extracellular cyclic nucleotide phosphodiesterase shares several key characteristics with preparations of phosphodiesterases from pea (Lin and Varner, 1972), barley (Vandepeute et al, 1973), potato (Ashton and Polya, 1975;Zan-Kowalczewska et al, 1984), sunflower (Junker et al, 1977), spinach (Brown et al, 1980), lettuce (Chiatante et al, 1988), or Lemna (Gangwani et al, 1994, such as molecular mass of the monomer unit (65-80 kD), an acidic pH optimum (pH 5-7), lack of requirement for bivalent metal ions, and broad substrate specificity. In general, higher plant cyclic nucleotide phosphodiesterases of this class hydrolyze, irrespective of the nucleobase present, 2Ј:3Ј-cyclic NMP to 3Ј-NMP at a higher rate than 3Ј:5Ј-cyclic NMP to a mixture of 3Ј-NMP and 5Ј-NMP, typically in a ratio of 7 to 1 (Lin and Varner, 1972), which is similar to the ratio observed for the tomato enzyme (6:1).…”

Section: Discussionmentioning

confidence: 98%

Induction of an Extracellular Cyclic Nucleotide Phosphodiesterase as an Accessory Ribonucleolytic Activity during Phosphate Starvation of Cultured Tomato Cells

et al. 2000

View full text Add to dashboard Cite

During growth under conditions of phosphate limitation, suspension-cultured cells of tomato (Lycopersicon esculentumMill.) secrete phosphodiesterase activity in a similar fashion to phosphate starvation-inducible ribonuclease (RNase LE), a cyclizing endoribonuclease that generates 2:3-cyclic nucleoside monophosphates (NMP) as its major monomeric products (T. Nü rnberger, S. Abel, W. Jost, K. Glund [1990] Plant Physiol 92: 970-976). Tomato extracellular phosphodiesterase was purified to homogeneity from the spent culture medium of phosphate-starved cells and was characterized as a cyclic nucleotide phosphodiesterase. The purified enzyme has a molecular mass of 70 kD, a pH optimum of 6.2, and an isoelectric point of 8.1. The phosphodiesterase preparation is free of any detectable deoxyribonuclease, ribonuclease, and nucleotidase activity. Tomato extracellular phosphodiesterase is insensitive to EDTA and hydrolyzes with no apparent base specificity 2:3-cyclic NMP to 3-NMP and the 3:5-cyclic isomers to a mixture of 3-NMP and 5-NMP. Specific activities of the enzyme are 2-fold higher for 2:3-cyclic NMP than for 3:5-cyclic isomers. Analysis of monomeric products of sequential RNA hydrolysis with purified RNase LE, purified extracellular phosphodiesterase, and cleared ؊Pi culture medium as a source of 3-nucleotidase activity indicates that cyclic nucleotide phosphodiesterase functions as an accessory ribonucleolytic activity that effectively hydrolyzes primary products of RNase LE to substrates for phosphate-starvationinducible phosphomonoesterases. Biosynthetical labeling of cyclic nucleotide phopshodiesterase upon phosphate starvation suggests de novo synthesis and secretion of a set of nucleolytic enzymes for scavenging phosphate from extracellular RNA substrates.

show abstract

“…In contrast, the I c phosphodiesterase had highest activity with 3h,5h-cGMP and 3h,5h-cAMP and little activity with their 2h,3h isomers, had a less acidic pH optimum of 6.1, was sensitive to inhibition by methylxanthines, and liberated 5h-mononucleotides as the main product ; it also displayed sensitivity to endogenous protein effectors and was activated by Ca# + (Brown et al, 1979b). Further examination of I c phosphodiesterase revealed that it occurred in multienzyme complexes of molecular mass 187 and 370 kDa in association with acid phosphatase, ribonuclease, nucleotidase and ATPase (Brown et al, 1980a).…”

Section: mentioning

confidence: 99%

Tansley Review No. 106

et al. 1999

Self Cite

View full text Add to dashboard Cite

 For three decades, hypotheses relating to the occurrence and function of cyclic nucleotides in higher plants have been highly controversial. Although cyclic nucleotides had been shown to have key regulatory roles in animals and bacteria, investigations with higher plants in the 1970s and early 1980s were criticized on the basis of (i) a lack of specificity of effects apparently elicited by cyclic nucleotides, (ii) the equivocal identification of putative endogenous cyclic nucleotides and (iii) ambiguity in the identification of enzymes connected with cyclic nucleotide. More recent evidence based on more rigorous identification procedures has demonstrated conclusively the presence of cyclic nucleotides, nucleotidyl cyclases and cyclic nucleotide phosphodiesterases in higher plants, and has identified plant processes subject to regulation by cyclic nucleotides. Here we review the history of the debate, the recent evidence establishing the presence of these compounds and their role ; future research objectives are discussed.

show abstract

The cyclic nucleotide phosphodiesterases of spinach chloroplasts and microsomes

Cited by 34 publications

References 20 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

Induction of an Extracellular Cyclic Nucleotide Phosphodiesterase as an Accessory Ribonucleolytic Activity during Phosphate Starvation of Cultured Tomato Cells

Tansley Review No. 106

Contact Info

Product

Resources

About

The cyclic nucleotide phosphodiesterases of spinach chloroplasts and microsomes

Cited by 34 publications

References 20 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

Induction of an Extracellular Cyclic Nucleotide Phosphodiesterase as an Accessory Ribonucleolytic Activity during Phosphate Starvation of Cultured Tomato Cells

Tansley Review No. 106

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