6533b7dafe1ef96bd126e105

RESEARCH PRODUCT

Nitric oxide inhibits the ATPase activity of the chaperone-like AAA+ ATPase CDC48, a target for S-nitrosylation in cryptogein signalling in tobacco cells

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NO has important physiological functions in plants, including the adaptative response to pathogen attack. We previously demonstrated that cryptogein, an elicitor of defence reaction produced by the oomycete Phytophthora cryptogea , triggers NO synthesis in tobacco. To decipher the role of NO in tobacco cells elicited by cryptogein, in the present study we performed a proteomic approach in order to identify proteins undergoing S-nitrosylation. We provided evidence that cryptogein induced the S-nitrosylation of several proteins and identified 11 candidates, including CDC48 (cell division cycle 48), a member of the AAA+ ATPase (ATPase associated with various cellular activities) family. In vitro , NtCDC48 ( Nicotiana tabacum CDC48) was shown to be poly-S-nitrosylated by NO donors and we could identify Cys 110 , Cys 526 and Cys 664 as a targets for S-nitrosylation. Cys 526 is located in the Walker A motif of the D2 domain, that is involved in ATP binding and was previously reported to be regulated by oxidative modification in Drosophila . We investigated the consequence of NtCDC48 S-nitrosylation and found that NO abolished NtCDC48 ATPase activity and induced slight conformation changes in the vicinity of Cys 526 . Similarly, substitution of Cys 526 by an alanine residue had an impact on NtCDC48 activity. More generally, the present study identified CDC48 as a new candidate for S-nitrosylation in plants facing biotic stress and further supports the importance of Cys 526 in the regulation of CDC48 by oxidative/nitrosative agents.