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Nucleocytoplasmic partitioning of tobacco N receptor is modulated by SGT 1
Author(s) -
Hoser Rafał,
Żurczak Marek,
Lichocka Małgorzata,
Zuzga Sabina,
Dadlez Michal,
Samuel Marcus A.,
Ellis Brian E.,
Stuttmann Johannes,
Parker Jane E.,
Hennig Jacek,
Krzymowska Magdalena
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12347
Subject(s) - phosphorylation , nicotiana tabacum , mapk/erk pathway , tobacco mosaic virus , mutant , microbiology and biotechnology , biology , arabidopsis , chemistry , biochemistry , genetics , gene , virus
SummarySGT 1 ( S uppressor of G2 allele of SKP 1) is required to maintain plant disease R esistance (R) proteins with N ucleotide‐ B inding ( NB ) and L eucine‐ R ich R epeat ( LRR ) domains in an inactive but signaling‐competent state. SGT 1 is an integral component of a multi‐protein network that includes RACK 1, Rac1, RAR 1, Rboh, HSP 90 and HSP 70, and in rice the M itogen‐ A ctivated P rotein K inase ( MAPK ), Os MAPK 6. Tobacco ( Nicotiana tabacum ) N protein, which belongs to the T oll‐ I nterleukin R eceptor ( TIR )‐ NB ‐ LRR class of R proteins, confers resistance to T obacco M osaic V irus ( TMV ). Following transient expression in planta , we analyzed the functional relationship between SGT 1, SIPK – a tobacco MAPK 6 ortholog – and N, using mass spectrometry, confocal microscopy and pathogen assays. Here, we show that tobacco SGT 1 undergoes specific phosphorylation in a canonical MAPK target‐motif by SIPK . Mutation of this motif to mimic SIPK phosphorylation leads to an increased proportion of cells displaying SGT 1 nuclear accumulation and impairs N‐mediated resistance to TMV , as does phospho‐null substitution at the same residue. Forced nuclear localization of SGT 1 causes N to be confined to nuclei. Our data suggest that one mode of regulating nucleocytoplasmic partitioning of R proteins is by maintaining appropriate levels of SGT 1 phosphorylation catalyzed by plant MAPK .