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Trafficking of the myrosinase‐associated protein GLL 23 requires NUC / MVP 1/ GOLD 36/ ERMO 3 and the p24 protein CYB
Author(s) -
Jancowski Sylwia,
Catching Amanda,
Pighin Jamie,
Kudo Takamasa,
Foissner Ilse,
Wasteneys Geoffrey O.
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12408
Subject(s) - endoplasmic reticulum , myrosinase , microbiology and biotechnology , vacuolar protein sorting , mutant , cytoplasm , biology , wild type , transport protein , unfolded protein response , chemistry , biochemistry , gene , glucosinolate , vacuole , agronomy , brassica
Summary Proteins detrimental to endoplasmic reticulum ( ER ) morphology need to be efficiently exported. Here, we identify two mechanisms that control trafficking of A rabidopsis thaliana GLL 23, a 43 kDa GDSL ‐like lipase implicated in glucosinolate metabolism through its association with the β‐glucosidase myrosinase. Using immunofluorescence, we identified two mutants that showed aberrant accumulation of GLL 23: large perinuclear ER aggregates in the nuclear cage ( nuc ) mutant; and small compartments contiguous with the peripheral ER in the cytoplasmic bodies ( cyb ) mutant. Live imaging of fluorescently tagged GLL23 confirmed its presence in the nuc and cyb compartments, but lack of fluorescent signals in the wild‐type plants suggested that GLL 23 is normally post‐translationally modified for ER export. NUC encodes the MVP 1/ GOLD 36/ ERM O3 myrosinase‐associated protein, previously shown to have vacuolar distribution. CYB is an ER and G olgi‐localized p24 type I membrane protein component of coat protein complex ( COP ) vesicles, animal and yeast homologues of which are known to be involved in selective cargo sorting for ER – G olgi export. Without NUC , GLL 23 accumulates in the ER this situation suggests that NUC is in fact active in the ER . Without CYB , both GLL 23 and NUC were found to accumulate in cyb compartments, consistent with a role for NUC in GLL 23 processing and indicated that GLL 23 is the likely sorting target of the CYB p24 protein.