Resistance proteins: molecular switches of plant defence.
Specificity of the plant innate immune system is often conferred by resistance (R) proteins. Most R proteins contain leucine-rich repeats (LRRs), a central nucleotide-binding site (NBS) and a variable amino-terminal domain. The LRRs are mainly involved in recognition, whereas the amino-terminal domain determines signalling specificity. The NBS forms part of a nucleotide binding (NB)-ARC domain that presumably functions as a molecular switch. The conserved nature of NB-ARC proteins makes it possible to map mutations of R protein residues onto the crystal structures of related NB-ARC proteins, providing hypotheses for the functional roles of these residues. A functional model emerges in which the LRRs control the molecular state of the NB-ARC domain. Pathogen recognition triggers nucleotide-dependent conformational changes that might induce oligomerisation, thereby providing a scaffold for activation of downstream signalling components.
Takken
Frank Lw
FL
Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, PO Box 94062, 1090 GB Amsterdam, The Netherlands. f.l.w.takken@uva.nl
Albrecht
Mario
M
Tameling
Wladimir Il
WI
D008967:Molecular Biology; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation
D010940:Plant Proteins