title: Structural basis for assembly and function of a heterodimeric plant immune receptor.
abstract: Cytoplasmic plant immune receptors recognize specific pathogen effector proteins and initiate effector-triggered immunity. In Arabidopsis, the immune receptors RPS4 and RRS1 are both required to activate defense to three different pathogens. We show that RPS4 and RRS1 physically associate. Crystal structures of the N-terminal Toll-interleukin-1 receptor/resistance (TIR) domains of RPS4 and RRS1, individually and as a heterodimeric complex (respectively at 2.05, 1.75, and 2.65 angstrom resolution), reveal a conserved TIR/TIR interaction interface. We show that TIR domain heterodimerization is required to form a functional RRS1/RPS4 effector recognition complex. The RPS4 TIR domain activates effector-independent defense, which is inhibited by the RRS1 TIR domain through the heterodimerization interface. Thus, RPS4 and RRS1 function as a receptor complex in which the two components play distinct roles in recognition and signaling.
authors.affiliation: School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Williams
authors.forename: Kee Hoon
authors.initials: KH
authors.lastname: Sohn
authors.forename: Li
authors.initials: L
authors.lastname: Wan
authors.forename: Maud
authors.initials: M
authors.lastname: Bernoux
authors.forename: Panagiotis F
authors.initials: PF
authors.lastname: Sarris
authors.forename: Cecile
authors.initials: C
authors.lastname: Segonzac
authors.forename: Thomas
authors.initials: T
authors.lastname: Ve
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Simon B
authors.initials: SB
authors.lastname: Saucet
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Ericsson
authors.forename: Lachlan W
authors.initials: LW
authors.lastname: Casey
authors.forename: Thierry
authors.initials: T
authors.lastname: Lonhienne
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Winzor
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Anne
authors.initials: A
authors.lastname: Coerdt
authors.forename: Jane E
authors.initials: JE
authors.lastname: Parker
authors.forename: Peter N
authors.initials: PN
authors.lastname: Dodds
authors.forename: Bostjan
authors.initials: B
authors.lastname: Kobe
authors.forename: Jonathan D G
authors.initials: JD
authors.lastname: Jones
mesh_terms: D060054:Agrobacterium / Q000502:physiology; D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism; D016923:Cell Death; D018360:Crystallography, X-Ray; D007113:Immunity, Innate; D008958:Models, Molecular; D009154:Mutation; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014026:Nicotiana / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology
chemical_list: D029681:Arabidopsis Proteins; C098294:AvrRps4 protein, Pseudomonas syringae; D001426:Bacterial Proteins; D010940:Plant Proteins; C582898:RRS1 protein, Arabidopsis; D011971:Receptors, Immunologic; C097421:rps4 protein, plant