title: Membrane microdomains and the cytoskeleton constrain AtHIR1 dynamics and facilitate the formation of an AtHIR1-associated immune complex.
abstract: Arabidopsis hypersensitive-induced reaction (AtHIR) proteins function in plant innate immunity. However, the underlying mechanisms by which AtHIRs participate in plant immunity remain elusive. Here, using VA-TIRFM and FLIM-FRET, we revealed that AtHIR1 is present in membrane microdomains and co-localizes with the membrane microdomain marker REM1.3. Single-particle tracking analysis revealed that membrane microdomains and the cytoskeleton, especially microtubules, restrict the lateral mobility of AtHIR1 at the plasma membrane and facilitate its oligomerization. Furthermore, protein proximity index measurements, fluorescence cross-correlation spectroscopy, and biochemical experiments demonstrated that the formation of the AtHIR1 complex upon pathogen perception requires intact microdomains and cytoskeleton. Taken together, these findings suggest that microdomains and the cytoskeleton constrain AtHIR1 dynamics, promote AtHIR1 oligomerization, and increase the efficiency of the interactions of AtHIR1 with components of the AtHIR1 complex in response to pathogens, thus providing valuable insight into the mechanisms of defense-related responses in plants.
authors.affiliation: College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Lv
authors.affiliation: College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Jing
authors.affiliation: College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, 06520, USA.
authors.forename: Yongdeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, 47907, USA.
authors.forename: Yingfang
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, 47907, USA.
authors.forename: Russell
authors.initials: R
authors.lastname: Julian
authors.affiliation: College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Lin
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism*; D021962:Membrane Microdomains / Q000235:genetics / Q000378:metabolism*; D057865:Plant Immunity / Q000235:genetics / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins
keywords: 
  Arabidopsis thaliana
  ; AtHIR1; cytoskeleton; lateral mobility; membrane microdomain; single-particle analysis