Cytosolic HSP90 associates with and modulates the Arabidopsis RPM1 disease resistance protein.
The Arabidopsis protein RPM1 activates disease resistance in response to Pseudomonas syringae proteins targeted to the inside of the host cell via the bacterial type III delivery system. We demonstrate that specific mutations in the ATP-binding domain of a single Arabidopsis cytosolic HSP90 isoform compromise RPM1 function. These mutations do not affect the function of related disease resistance proteins. RPM1 associates with HSP90 in plant cells. The Arabidopsis proteins RAR1 and SGT1 are required for the action of many R proteins, and display some structural similarity to HSP90 co-chaperones. Each associates with HSP90 in plant cells. Our data suggest that (i) RPM1 is an HSP90 client protein; and (ii) RAR1 and SGT1 may function independently as HSP90 cofactors. Dynamic interactions among these proteins can regulate RPM1 stability and function, perhaps similarly to the formation and regulation of animal steroid receptor complexes.
Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
David A
DA
Hubert
Pablo
P
Tornero
Youssef
Y
Belkhadir
Priti
P
Krishna
Akira
A
Takahashi
Ken
K
Shirasu
Jeffery L
JL
Dangl
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010940:Plant Proteins / Q000378:metabolism; D044224:Pseudomonas syringae / Q000472:pathogenicity; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D018841:HSP90 Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; C499581:PBS2 protein, Arabidopsis; D010940:Plant Proteins; C095014:RPM1 protein, Arabidopsis; C452192:SGT1b protein, Arabidopsis