title: HSP90 interacts with RAR1 and SGT1 and is essential for RPS2-mediated disease resistance in Arabidopsis.
abstract: RAR1 and its interacting partner SGT1 play a central role in plant disease resistance triggered by a number of resistance (R) proteins. We identified cytosolic heat shock protein 90 (HSP90), a molecular chaperone, as another RAR1 interacting protein by yeast two-hybrid screening. RAR1 interacts with the N-terminal half of HSP90 that contains the ATPase domain. HSP90 also specifically interacts with SGT1 that contains a tetratricopeptide repeat motif and a domain with similarity to the cochaperone p23. In Arabidopsis, the HSP90 inhibitor geldanamycin reduces the hypersensitive response and abolishes resistance triggered by the R protein RPS2 against Pseudomonas syringae pv. tomato DC3000 (avrRpt2). One of four Arabidopsis cytosolic HSP90 isoforms, AtHSP90.1 is required for full RPS2 resistance and is rapidly induced upon pathogen challenge. We propose that RAR1 and SGT1 function closely with HSP90 in chaperoning roles that are essential for disease resistance.
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000382:microbiology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D017931:DNA Primers; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism; D011549:Pseudomonas / Q000472:pathogenicity; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D017931:DNA Primers; D018841:HSP90 Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; C499581:PBS2 protein, Arabidopsis; D010940:Plant Proteins; C452191:SGT1a protein, Arabidopsis