MODIFIED VACUOLE PHENOTYPE1 is an Arabidopsis myrosinase-associated protein involved in endomembrane protein trafficking.
We identified an Arabidopsis (Arabidopsis thaliana) ethyl methanesulfonate mutant, modified vacuole phenotype1-1 (mvp1-1), in a fluorescent confocal microscopy screen for plants with mislocalization of a green fluorescent protein-delta tonoplast intrinsic protein fusion. The mvp1-1 mutant displayed static perinuclear aggregates of the reporter protein. mvp1 mutants also exhibited a number of vacuole-related phenotypes, as demonstrated by defects in growth, utilization of stored carbon, gravitropic response, salt sensitivity, and specific susceptibility to the fungal necrotroph Alternaria brassicicola. Similarly, crosses with other endomembrane marker fusions identified mislocalization to aggregate structures, indicating a general defect in protein trafficking. Map-based cloning showed that the mvp1-1 mutation altered a gene encoding a putative myrosinase-associated protein, and glutathione S-transferase pull-down assays demonstrated that MVP1 interacted specifically with the Arabidopsis myrosinase protein, THIOGLUCOSIDE GLUCOHYDROLASE2 (TGG2), but not TGG1. Moreover, the mvp1-1 mutant showed increased nitrile production during glucosinolate hydrolysis, suggesting that MVP1 may play a role in modulation of myrosinase activity. We propose that MVP1 is a myrosinase-associated protein that functions, in part, to correctly localize the myrosinase TGG2 and prevent inappropriate glucosinolate hydrolysis that could generate cytotoxic molecules.
Agee
April E
AE
Center for Plant Cell Biology, University of California, Riverside, California 92521, USA.
Surpin
Marci
M
Sohn
Eun Ju
EJ
Girke
Thomas
T
Rosado
Abel
A
Kram
Brian W
BW
Carter
Clay
C
Wentzell
Adam M
AM
Kliebenstein
Daniel J
DJ
Jin
Hak Chul
HC
Park
Ohkmae K
OK
Jin
Hailing
H
Hicks
Glenn R
GR
Raikhel
Natasha V
NV
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D005961:Glucosinolates / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010802:Phylogeny; D021381:Protein Transport / Q000502:physiology*; D036226:Seedlings / Q000166:cytology / Q000378:metabolism
D029681:Arabidopsis Proteins; D005961:Glucosinolates; D006026:Glycoside Hydrolases; C511863:TGG2 protein, Arabidopsis