title: HSP90s are required for NLR immune receptor accumulation in Arabidopsis.
abstract: Heat shock proteins (HSPs) serve as molecular chaperones for diverse client proteins in many biological processes. In plant immunity, cytosolic HSP90s participate in the assembly, stability control and/or activation of immune receptor complexes. In this paper we report that in addition to the well-established positive roles that HSP90 isoforms play in plant immunity, they are also involved in the negative regulation of immune receptor accumulation. Point mutations in two HSP90 genes, HSP90.2 and HSP90.3, were identified from a forward genetic screen designed to isolate mutants with enhanced disease resistance. We found that specific mutations in HSP90.2 and HSP90.3 lead to heightened accumulation of immune receptors, including SNC1, RPS2 and RPS4. HSP90s may assist SGT1 in the formation of SCF E3 ubiquitin ligase complexes that target immune receptors for degradation. Such regulation is critical for maintaining appropriate levels of immune receptor proteins to avoid autoimmunity.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
authors.forename: Shuai
authors.initials: S
authors.lastname: Huang
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Monaghan
authors.forename: Xionghui
authors.initials: X
authors.lastname: Zhong
authors.forename: Ling
authors.initials: L
authors.lastname: Lin
authors.forename: Tongjun
authors.initials: T
authors.lastname: Sun
authors.forename: Oliver Xiaoou
authors.initials: OX
authors.lastname: Dong
authors.forename: Xin
authors.initials: X
authors.lastname: Li
mesh_terms: D017360:Arabidopsis / Q000276:immunology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D057865:Plant Immunity / Q000235:genetics / Q000276:immunology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018841:HSP90 Heat-Shock Proteins; D010940:Plant Proteins; C089426:RPS2 protein, Arabidopsis; C482739:SNC1 protein, Arabidopsis; C097421:rps4 protein, plant; D044843:SKP Cullin F-Box Protein Ligases; D005964:Glucosyltransferases; C515668:SGT1 protein, Arabidopsis
keywords: Arabidopsis; HSP90; NLR; RPS2; RPS4; SGT1; SKP1-Cullin 1-F-Box; SNC1; plant immunity; resistance protein turnover