The coiled-coil and nucleotide binding domains of the Potato Rx disease resistance protein function in pathogen recognition and signaling.
Plant genomes encode large numbers of nucleotide binding and leucine-rich repeat (NB-LRR) proteins, some of which mediate the recognition of pathogen-encoded proteins. Following recognition, the initiation of a resistance response is thought to be mediated by the domains present at the N termini of NB-LRR proteins, either a Toll and Interleukin-1 Receptor or a coiled-coil (CC) domain. In order to understand the role of the CC domain in NB-LRR function, we have undertaken a systematic structure-function analysis of the CC domain of the potato (Solanum tuberosum) CC-NB-LRR protein Rx, which confers resistance to Potato virus X. We show that the highly conserved EDVID motif of the CC domain mediates an intramolecular interaction that is dependent on several domains within the rest of the Rx protein, including the NB and LRR domains. Other conserved and nonconserved regions of the CC domain mediate the interaction with the Ran GTPase-activating protein, RanGAP2, a protein required for Rx function. Furthermore, we show that the Rx NB domain is sufficient for inducing cell death typical of hypersensitive plant resistance responses. We describe a model of CC-NB-LRR function wherein the LRR and CC domains coregulate the signaling activity of the NB domain in a recognition-specific manner.
Rairdan
Gregory J
GJ
Boyce Thompson Institute for Plant Research, Ithaca, New York 14853.
Collier
Sarah M
SM
Sacco
Melanie A
MA
Baldwin
Thomas T
TT
Boettrich
Teresa
T
Moffett
Peter
P
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D020868:Gene Silencing; D007113:Immunity, Innate / Q000235:genetics; D000090263:Leucine-Rich Repeat Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017863:Potexvirus / Q000254:growth & development*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D011198:Solanum tuberosum / Q000235:genetics* / Q000378:metabolism / Q000821:virology
D000090263:Leucine-Rich Repeat Proteins; D010940:Plant Proteins; D011506:Proteins