Nitric oxide (NO) is a small redox molecule that acts as a signal in different physiological and stress-related processes in plants.Recent evidence suggests that the biological activity of NO is also mediated by S-nitrosylation, a well-known redox-basedposttranslational protein modification. Here, we show that during programmed cell death (PCD), induced by both heatshock (HS) or hydrogen peroxide (H2O2) in tobacco (Nicotiana tabacum) Bright Yellow-2 cells, an increase in S-nitrosylating agentsoccurred. NO increased in both experimentally induced PCDs, although with different intensities. In H2O2-treated cells, theincrease in NO was lower than in cells exposed to HS. However, a simultaneous increase in S-nitrosoglutathione (GSNO),another NO source for S-nitrosylation, occurred in H2O2-treated cells, while a decrease in this metabolite was evident after HS.Consistently, different levels of activity and expression of GSNO reductase, the enzyme responsible for GSNO removal, werefound in cells subjected to the two different PCD-inducing stimuli: low in H2O2-treated cells and high in the heat-shocked ones.Irrespective of the type of S-nitrosylating agent, S-nitrosylated proteins formed upon exposure to both of the PCD-inducingstimuli. Interestingly, cytosolic ascorbate peroxidase (cAPX), a key enzyme controlling H2O2 levels in plants, was found to beS-nitrosylated at the onset of both PCDs. In vivo and in vitro experiments showed that S-nitrosylation of cAPX was responsiblefor the rapid decrease in its activity. The possibility that S-nitrosylation induces cAPX ubiquitination and degradation and acts aspart of the signaling pathway leading to PCD is discussed.

S-Nitrosylation of ascorbate peroxidase is part of the programmed cell death signaling in tobacco BY-2 cells

Locato V;De Gara L
2013-01-01

Abstract

Nitric oxide (NO) is a small redox molecule that acts as a signal in different physiological and stress-related processes in plants.Recent evidence suggests that the biological activity of NO is also mediated by S-nitrosylation, a well-known redox-basedposttranslational protein modification. Here, we show that during programmed cell death (PCD), induced by both heatshock (HS) or hydrogen peroxide (H2O2) in tobacco (Nicotiana tabacum) Bright Yellow-2 cells, an increase in S-nitrosylating agentsoccurred. NO increased in both experimentally induced PCDs, although with different intensities. In H2O2-treated cells, theincrease in NO was lower than in cells exposed to HS. However, a simultaneous increase in S-nitrosoglutathione (GSNO),another NO source for S-nitrosylation, occurred in H2O2-treated cells, while a decrease in this metabolite was evident after HS.Consistently, different levels of activity and expression of GSNO reductase, the enzyme responsible for GSNO removal, werefound in cells subjected to the two different PCD-inducing stimuli: low in H2O2-treated cells and high in the heat-shocked ones.Irrespective of the type of S-nitrosylating agent, S-nitrosylated proteins formed upon exposure to both of the PCD-inducingstimuli. Interestingly, cytosolic ascorbate peroxidase (cAPX), a key enzyme controlling H2O2 levels in plants, was found to beS-nitrosylated at the onset of both PCDs. In vivo and in vitro experiments showed that S-nitrosylation of cAPX was responsiblefor the rapid decrease in its activity. The possibility that S-nitrosylation induces cAPX ubiquitination and degradation and acts aspart of the signaling pathway leading to PCD is discussed.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12610/5819
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 107
  • ???jsp.display-item.citation.isi??? 86
social impact