The Hop/Sti1-Hsp90 chaperone complex facilitates the maturation and transport of a PAMP receptor in rice innate immunity.
Recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs) represents a critical first step of innate defense in plants and animals. However, maturation and transport of PRRs are not well understood. We find that the rice chitin receptor OsCERK1 interacts with Hsp90 and its cochaperone Hop/Sti1 in the endoplasmic reticulum (ER). Hop/Sti1 and Hsp90 are required for efficient transport of OsCERK1 from the ER to the plasma membrane (PM) via a pathway dependent on Sar1, a small GTPase which regulates ER-to-Golgi trafficking. Further, Hop/Sti1 and Hsp90 are present at the PM in a complex (designated the "defensome") with OsRac1, a plant-specific Rho-type GTPase. Finally, Hop/Sti1 was required for chitin-triggered immunity and resistance to rice blast fungus. Our results suggest that the Hop/Sti1-Hsp90 chaperone complex plays an important and likely conserved role in the maturation and transport of PRRs and may function to link PRRs and Rac/Rop GTPases.
Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, Takayama, Ikoma, Japan.
Letian
L
Chen
Satoshi
S
Hamada
Masayuki
M
Fujiwara
Tingheng
T
Zhu
Nguyen Phuong
NP
Thao
Hann Ling
HL
Wong
Priti
P
Krishna
Takashi
T
Ueda
Hanae
H
Kaku
Naoto
N
Shibuya
Tsutomu
T
Kawasaki
Ko
K
Shimamoto
D000818:Animals; D007113:Immunity, Innate; D018832:Molecular Chaperones / Q000378:metabolism*; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism; D012275:Oryza / Q000276:immunology*; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011499:Protein Processing, Post-Translational; D011971:Receptors, Immunologic / Q000378:metabolism*
D018832:Molecular Chaperones; D010940:Plant Proteins; D011971:Receptors, Immunologic; D020559:Monomeric GTP-Binding Proteins