Multiple Domain Associations within the Arabidopsis Immune Receptor RPP1 Regulate the Activation of Programmed Cell Death
Fig 5
The TIR domain inhibits RPP1 self-association in the absence of the effector ATR1.
(A) RPP1_NdA constructs lacking the TIR domain self-associate in an effector-independent manner. Differentially epitope-tagged versions of either NB-ARC-LRR or LRR proteins were transiently expressed in N. benthamiana and samples were collected at 48 hours post-infiltration (hpi) for co-immunoprecipitation using α-Flag agarose beads. Asterisks indicate non-specific bands. Staining of RuBisCO with Ponceau S provides a loading control. (B) The TIR domain alone is responsible for inhibiting RPP1 self-association, as N-terminal truncations up to the TIR domain retain effector-dependent self-association. Co-immunoprecipitation experiments were performed using differentially tagged proteins as in (A) except that tissue samples were collected at 36 hpi (E = ATR1_Emoy2, C = ATR1_Cala2). The expression of ATR1:citrine was detected with an α-GFP antibody. The specific amino acids comprising each construct are indicated in subscript. Experiments were performed three times with similar results.