The nuclear dynamic of CDC48 is affected during the immune response in plants

Plants are continuously challenged by a myriad of pathogenic microorganisms, including bacteria, viruses, fungi and oomycetes, against which they must defend themselves. The protein Cell Division Cycle 48 (CDC48), a key player of ubiquitin-proteasome system which segregates and remodels ubiquitinated proteins for degradation, is known to be mobilized during plant immunity. Moreover, the characterization of the nuclear role of CDC48 is of interest, in particular its regulation in nuclear processes such as chromatin remodeling, DNA repair and gene expression. In this regard, its nuclear functions during plant immunity remain underexplored. This study investigates the dynamics of CDC48 during plant immune responses. The biophysical analysis using the Fluorescence Correlation Spectroscopy (FCS) on tobacco leaves stably overexpressing GFP-CDC48 revealed that the nuclear dynamics of CDC48 changed after treatment with cryptogein, an elicitor of immune responses. FCS analysis revealed an increase of the nuclear mobility of CDC48 and a faster interaction of CDC48 with a wide range of nuclear partners shortly after cryptogein treatment. Overall, our study shows a nuclear regulation of the interaction of CDC48 with its potential partners and sheds new light on potential nuclear involvements of CDC48 following the triggering of defense mechanisms.