SUMOylation contributes to proteostasis of the chloroplast protein import receptor TOC159 during early development

  1. Sonia Accossato
  2. Felix Kessler  Is a corresponding author
  3. Venkatasalam Shanmugabalaji  Is a corresponding author
  1. Laboratory of Plant Physiology, University of Neuchâtel, Switzerland
6 figures, 1 table and 2 additional files

Figures

Figure 1 with 2 supplements
Small ubiquitin-related modifier (SUMO) interaction and SUMOylation of TOC159GM.

(A) Schematic representation of TOC159GM indicating the predicted SUMO-interacting motif (SIM) in the G-domain. (B) Yeast two-hybrid interaction assay of TOC159 G with SUMO proteins on –Leu, –Trp …

Figure 1—figure supplement 1
Yeast two-hybrid interaction assay of TOC159 M-domain with SUMO proteins on –Leu, –Trp and –Leu, –Trp, and –His medium.

AD, activation domain; BD, binding domain; empty vector was used as a control.

Figure 1—figure supplement 2
Predicted SUMOylation sites at TOC159GM and in planta SUMOylation assay.

(A) Predicted SUMOylation sites at TOC159GM domain using the GPS-SUMO prediction algorithm with a high threshold (http://sumosp.biocuckoo.org/online.php). (B) Transient expression of GFP, …

Figure 2 with 1 supplement
Complementation of ppi2 (toc159 mutant) by non-SUMOylatable TOC159GM-K/R.

(A) Phenotypes of 7 days old seedling of ppi2, WT (Ws), GFP-TOC159GM:ppi2, and GFP-TOC159GM-K/R:ppi2. (B) Western blot analysis of total protein extracts from 7 days old seedlings of WT (Ws), …

Figure 2—figure supplement 1
Screening of ppi2 plants for complementation with GFP-TOC159GM and GFP-TOC159GM-K/R.

(A) Genotyping of two independent plant lines (3.1 and 3.12) expressing GFP-TOC159GM in the ppi2 background (GFP-TOC159GM:ppi2) and two independent plant lines (4.2 and 4.8) expressing …

Figure 3 with 5 supplements
SUMOylation partially protects TOC159 from UPS-mediated degradation.

(A) Immunoblotting of total protein extracts from 3 days old seedling of GFP-TOC159GM:ppi2 and GFP-TOC159GM-K/R:ppi2 grown in the presence or absence of paclobutrazol (PAC) (5 µM). WT (Ws) was used …

Figure 3—figure supplement 1
Immunoblotting of total protein extracts from two independent GFP-TOC159GM:ppi2 lines (3.1 and 3.12) and two independent GFP-TOC159GM-K/R:ppi2 lines (4.2 and 4.8).

Total protein was extracted from 3 days old seedlings grown in the presence or absence of PAC (5 µM). WT was used as the control for antibody specificity. The following antibodies were used GFP, …

Figure 3—figure supplement 2
Immunoblotting of total protein extracts from GFP-TOC159GM:ppi2 and GFP-TOC159GM-K/R:ppi2 grown in the presence or absence of PAC (5 µM).

WT was used as the control for antibody specificity. The following antibodies were used: GFP, TOC75, and TOC33 proteins. Actin was used as a loading control. The specific bands corresponding to GFP, …

Figure 3—figure supplement 3
RGL2 protein accumulation in GFP-TOC159GM:ppi2and GFP-TOC159GM-K/R:ppi2under low GA conditions.

(A) Immunoblotting of total protein extracts from two independent biological replicates of 3 days old GFP-TOC159GM:ppi2 and GFP-TOC159GM-K/R:ppi2 seedlings grown in the presence or absence of PAC (5 …

Figure 3—figure supplement 4
Total protein extracts of 3 days old GFP-TOC159GM:ppi2 or GFP-TOC159GM-K/R:ppi2 grown in the presence of PAC and further treated with or without MG132, analyzed by immunoblotting using antibodies against GFP.

UGPase was used as a loading control. The specific bands corresponding to GFP and UGPase were quantified. The quantified bands were normalized to GFP-TOC159GM in GFP-TOC159GM:ppi2 without MG132. …

Figure 3—figure supplement 5
The TOC159 SUMOylation-deficient line TOC159GM-K/R:ppi2 accumulates photosynthesis-associated proteins trended lower compared to TOC159GM:ppi2 under low GA conditions.

(A) Immunoblotting of total protein extracts from 3 days old seedling of GFP-TOC159GM:ppi2 and GFP-TOC159GM-K/R:ppi2 grown in the presence or absence of PAC (2 µM). The blot was probed with …

Hypothetical model for the SUMOylation-dependent fine-tuning of chloroplast biogenesis at the level of the TOC159 import receptor in early plant development.

Environmental conditions influence the concentrations of gibberellic acid (GA) that accumulate upon seed imbibition. When active GA levels are reduced by stress (-GA; left-hand panel), DELLA (RGL2) …

Author response image 1
A de-etiolation assay was carried out with WT, GFP-TOC159GM:ppi2 and GFP-TOC159GM-K/R:ppi2 plant lines (three independent biological replicates with at least 50 seedlings).

The seeds were stratified and exposed for 3h to 120 µmol x m-2 x s-1 of white light, then grown in the dark for 6 days. The etiolated seedlings were transferred to continuous light for two more …

Author response image 2
The TOC159 protein accumulation from GFP-TOC159GM:ppi2and GFP-TOC159GM-K/R:ppi2under low GA conditions and further treated with cycloheximide.

(A) Total protein extracts of three days old GFP-TOC159GM:ppi2 or GFP-TOC159GM-K/R:ppi2 grown seedlings grown on PAC and subsequently treated with or without cycloheximide were analyzed by …

Tables

Key resources table
Reagent type (species) or resourceDesignationSource or referenceIdentifiersAdditional information
Genetic reagent (Arabidopsis thaliana)pTOC159-GFP-TOC159GM:ppi2Shanmugabalaji et al., 2018
Genetic reagent (Arabidopsis thaliana)pTOC159-GFP-TOC159GM-K/RThis paper
Recombinant DNA reagentpGBKT7-TOC159GShanmugabalaji et al., 2018Yeast two-hybrid assay
Recombinant DNA reagentpGBKT7-TOC159MShanmugabalaji et al., 2018Yeast two-hybrid assay
Recombinant DNA reagentpGADT7-SUMO1This paperYeast two-hybrid assay
Recombinant DNA reagentpGADT7-SUMO2This paperYeast two-hybrid assay
Recombinant DNA reagentpGADT7-SUMO3This paperYeast two-hybrid assay
Recombinant DNA reagent35S-GFP-TOC159GMShanmugabalaji et al., 2018In planta CoIP
Recombinant DNA reagent35S-GFPThis paperIn planta CoIP
Recombinant DNA reagent35S-SUMO3-MYCThis paperIn planta CoIP
Recombinant DNA reagent35S-GFP-TOC159GM-K/R
This paper
In planta CoIP
AntibodyAnti-TOC75, rabbit polyclonalHiltbrunner et al., 20011:1000
AntibodyAnti-TOC33, rabbit polyclonalRahim et al., 20091:1000
AntibodyAnti-RGL2, rabbit polyclonalPiskurewicz et al., 20081:1000
AntibodyAnti-SUMO3, rabbit polyclonalAgriseraCat# AS083491:1000
AntibodyAnti-UGPase, rabbit polyclonalAgriseraCat# AS05086
RRID:AB_1031827
1:5000
AntibodyAnti-PSBA, rabbit polyclonalAgriseraCat# AS05084
RRID:AB_2172617
1:10,000
AntibodyAnti-PSBO1, rabbit polyclonalAgriseraCat# AS142824
RRID:AB_1031788
1:5000
AntibodyAnti-RBCL, rabbit polyclonalAgriseraCat# AS03037
RRID:AB_2175406
1:15,000
AntibodyAnti-RBCS, rabbit polyclonalAgriseraCat# AS07259
RRID:AB_1031806
1:5000
AntibodyAnti-PETC, rabbit polyclonalAgriseraCat# AS08330
RRID:AB_2162102
1:5000
AntibodyAnti-PSAD, rabbit polyclonalAgriseraCat# AS09461
RRID:AB_1832088
1:5000
AntibodyAnti-ATPC, rabbit polyclonalAgriseraCat# AS08312
RRID:AB_2290280
1:5000
AntibodyAnti-LHCB2, rabbit polyclonalAgriseraCat# AS01003
RRID:AB_1832080
1:10,000
AntibodyAnti-actin, mouse monoclonal antibodySigmaCat# A0480
RRID:AB_476670
1:2000
AntibodyAnti-GFP, mouse monoclonal antibodyTakaraCat#632380
RRID:AB_10013427
1:1000
AntibodyAnti-MYC, mouse monoclonal antibodyCell SignalingCat#2276
RRID:AB_331783
1:1000
AntibodyAnti-rabbit IgG conjugated with horseradish peroxidaseMilliporeCat# AP132P
RRID:AB_90264
1:10,000
AntibodyAnti-mouse IgG conjugated with horseradish peroxidaseSigmaCat# A5278
RRID:AB_258232
1:10,000
Strain, strain background (Escherichia coli)DH5αInvitrogenCat# 18265017
Strain, strain background (Agrobacterium tumefaciens)C58Community resource
Chemical compound, drugMG132AbMoleCat# M1902
Chemical compound, drugPaclobutrazolSigmaCat# 43900
Commercial assay or kitµMACS GFP-tagged beadsMiltenyi BiotechCat# 130091125
Software, algorithmImageQuant TLGE HealthcareRRID:SCR_014246
Software, algorithmGraphPad PrismGraphpadRRID:SCR_015807

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