The highly homologous NB-LRR resistance proteins Rx1 and Gpa2 consists of several domains with distinct functions in pathogen recognition, intermolecular interactions and signalling. The C-terminal half of the leucine-rich repeat domain(LRR), for example, is the main determinant of pathogen recognition specificity, whereas the nucleotide-binding domain alone is sufficient for the induction of a cell-death response. The three main domains of Rx and Gpa2; their N-terminal coiled coil, central nucleotide-binding domain and C-terminal LRR, all interact and can even form a functional protein when coexpressed as separate polypeptides. Interestingly, some of these interactions are released in the presence of avirulent pathogen effectors indicative of conformational changes that play a role in the regulation and activation of the R protein. Slight mismatches between the interacting domains can lead to strong autoactivation or loss-of-function. Rx1 and Gpa2 are distributed between the nucleus and cytoplasm and for Rx we could show that shifting this distribution to either subcellular compartment reduces its ability to initiate resistance against PVX. The finding that the individually expressed domains have strikingly different cellular distributions and that the introduction of a mutation in Rx that would disrupt nucleotide-binding leads 19 to a strong reduction in the nuclear localized Rx points to a link between conformation, activational state and subcellular localization. We hope to gain a further understanding of the functioning of resistance proteins by studying this link using in vivo spectroscopic techniques in combination with biochemical analyses of the domain interactions and cell fractionation assays.
|Title of host publication||Book of abstracts of COST FA 1208: Pathogen-informed strategies for sustainable broad-spectrum crop resistance|
|Publication status||Published - 2014|
|Event||COST FA 1208 Workshop on cellular dynamics of effector action and recognition, Toulouse, Frankrijk - |
Duration: 9 Apr 2014 → 11 Apr 2014
|Workshop||COST FA 1208 Workshop on cellular dynamics of effector action and recognition, Toulouse, Frankrijk|
|Period||9/04/14 → 11/04/14|