Ubiquitination in Immunity

Ubiquitin is a small (7.5 kDa) and highly conserved protein modifier. Attachment of ubiquitin by the ubiquitination system (UBS) which is composed by a three step enzymatic cascade condemns tagged proteins to degradation or to other fates, such as endocytosis or relocalization in the cell.

The UBS plays a key role in the regulation of processes triggered during plant immune responses and the integration of signaling through changes in hormone levels. The main goal of our group is the functional analysis of UBS components involved in the modulation of immune responses and the identification of proteins targeted for ubiquitination.

We combine several approaches including reverse genetics, cell-biology and biochemical methods to analyze the components of the UBS and to identify and characterize target proteins. Our work is mainly performed using the model plant Arabidopsis thaliana and to study the immune response in plants we employ several plant pathogens, such as the bacterial pathogen Pseudomonas syringae or the oomycete Hyaloperonospora arabidopsidis.

The UBS offers great opportunities for the improvement of crop plants. However, these have been hindered by our limited knowledge of the UBS and target proteins. Furthermore, it is of particular importance to widen our understanding of the ubiquitination process itself.