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RESEARCH PRODUCT

Functional characterization of the chaperon-like protein Cdc48 in cryptogein-induced immune response in tobacco. Communication orale et poster

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International audience; Cdc48, a molecular chaperone conserved in diff erent kingdoms, is a member of the AAA+ family contributing to numerous processes in mammalian including proteins quality control and degradation, vesicular traffi cking, autophagy and immunity. The functions of Cdc48 plant orthologues are less understood. We previously reported that Cdc48 is regulated by S-nitrosylation in tobacco cells undergoing an immune response triggered by cryptogein, an elicitin produced by the oomycete Phytophthora cryptogea. Here, we investigated the function of NtCdc48 in cryptogein signaling and induced hypersensitive-like cell death. NtCdc48 was found to accumulate in elicited cells both at the protein and transcript levels. Interestingly, only a small proportion of the overall NtCdc48 population appeared to be S-nitrosylated. Using gel fi ltration in native conditions, we confi rmed that NtCdc48 was present in its hexameric active form. An immunoprecipitation-based strategy followed my mass spectrometry analysis led to the identifi cation of about hundred NtCdc48 partners and underlined its contribution in cellular processes including targeting of ubiquitylated proteins for proteasome-dependent degradation, subcellular traffi cking and redox regulation. Finally, the analysis of cryptogein-induced-events in overexpressing NtCdc48 cells highlighted a correlation between NtCdc48 expression and hypersensitive cell death. Altogether, NtCdc48 is a component of cryptogein signaling and plant immunity.