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Plant immune and growth receptors share common signalling components but localise to distinct plasma membrane nanodomains

View Article: PubMed Central - PubMed

ABSTRACT

Cell surface receptors govern a multitude of signalling pathways in multicellular organisms. In plants, prominent examples are the receptor kinases FLS2 and BRI1, which activate immunity and steroid-mediated growth, respectively. Intriguingly, despite inducing distinct signalling outputs, both receptors employ common downstream signalling components, which exist in plasma membrane (PM)-localised protein complexes. An important question is thus how these receptor complexes maintain signalling specificity. Live-cell imaging revealed that FLS2 and BRI1 form PM nanoclusters. Using single-particle tracking we could discriminate both cluster populations and we observed spatiotemporal separation between immune and growth signalling platforms. This finding was confirmed by visualising FLS2 and BRI1 within distinct PM nanodomains marked by specific remorin proteins and differential co-localisation with the cytoskeleton. Our results thus suggest that signalling specificity between these pathways may be explained by the spatial separation of FLS2 and BRI1 with their associated signalling components within dedicated PM nanodomains.

Doi:: http://dx.doi.org/10.7554/eLife.25114.001

No MeSH data available.


Related in: MedlinePlus

Plasma membrane localisation of FLS2 and BRI1 with respect to the cytoskeleton.(A I–A IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (A I) and FLS2-GFP (A II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (A III) and a 3D surface plot of the raw data (A IV). (B I–B IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (B I) and FLS2-GFP (B II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (B III) and a 3D surface plot of the raw data (B IV). (C I–C IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (C I) and BRI1-GFP (C II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (C III) and a 3D surface plot of the raw data (C IV). (D I–D IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (D I) and BRI1-GFP (D II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (D III) and a 3D surface plot of the raw data (D IV). (E I–E IV) Confocal micrographs of TUB5-mCherry (E I) and FLS2-GFP (E II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (E III) and a 3D surface plot of the raw data (E IV). (F I–F IV) Confocal micrographs of TUA6-GFP (F I) and FLS2-mCherry (F II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (F III) and a 3D surface plot of the raw data (F IV). (G I–G IV) Confocal micrographs of TUB5-mCherry (G I) and BRI1-GFP (G II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (G III) and a 3D surface plot of the raw data (G IV). (H I–H IV) Confocal micrographs of TUA6-GFP (H I) and BRI1-mRFP (H II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (H III) and a 3D surface plot of the raw data (H IV). Fluorescence signals of cytoskeleton components are shown in magenta, fluorescence signals of FLS2 or BRI1 receptors are shown in green. The abbreviation tRFP stands for TagRFP. Scale bars represent 5 µm. The image series indicate that FLS2 and BRI1 receptor clusters repeatedly localised on top of actin filaments as indicated by white arrows in the respective 3D surface plots. In contrast, FLS2 and, to a minor extend, BRI1 receptors were largely excluded from plasma membrane areas that co-localised with cortical microtubules as indicated by white arrows in the respective 3D surface plots.DOI:http://dx.doi.org/10.7554/eLife.25114.005
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fig1s2: Plasma membrane localisation of FLS2 and BRI1 with respect to the cytoskeleton.(A I–A IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (A I) and FLS2-GFP (A II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (A III) and a 3D surface plot of the raw data (A IV). (B I–B IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (B I) and FLS2-GFP (B II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (B III) and a 3D surface plot of the raw data (B IV). (C I–C IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (C I) and BRI1-GFP (C II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (C III) and a 3D surface plot of the raw data (C IV). (D I–D IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (D I) and BRI1-GFP (D II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (D III) and a 3D surface plot of the raw data (D IV). (E I–E IV) Confocal micrographs of TUB5-mCherry (E I) and FLS2-GFP (E II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (E III) and a 3D surface plot of the raw data (E IV). (F I–F IV) Confocal micrographs of TUA6-GFP (F I) and FLS2-mCherry (F II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (F III) and a 3D surface plot of the raw data (F IV). (G I–G IV) Confocal micrographs of TUB5-mCherry (G I) and BRI1-GFP (G II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (G III) and a 3D surface plot of the raw data (G IV). (H I–H IV) Confocal micrographs of TUA6-GFP (H I) and BRI1-mRFP (H II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (H III) and a 3D surface plot of the raw data (H IV). Fluorescence signals of cytoskeleton components are shown in magenta, fluorescence signals of FLS2 or BRI1 receptors are shown in green. The abbreviation tRFP stands for TagRFP. Scale bars represent 5 µm. The image series indicate that FLS2 and BRI1 receptor clusters repeatedly localised on top of actin filaments as indicated by white arrows in the respective 3D surface plots. In contrast, FLS2 and, to a minor extend, BRI1 receptors were largely excluded from plasma membrane areas that co-localised with cortical microtubules as indicated by white arrows in the respective 3D surface plots.DOI:http://dx.doi.org/10.7554/eLife.25114.005

Mentions: In contrast to the highly mobile endomembrane compartments, the visualised FLS2- and BRI1-GFP clusters appeared rather immobile and seemed to follow a certain spatial organisation. FLS2 and BRI1 clusters often aligned in pearl chain-like structures and interconnected lines with low fluorescence intensities frequently separated by PM areas containing several receptor clusters, in particular for FLS2-GFP (Figure 1—figure supplement 2).


Plant immune and growth receptors share common signalling components but localise to distinct plasma membrane nanodomains
Plasma membrane localisation of FLS2 and BRI1 with respect to the cytoskeleton.(A I–A IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (A I) and FLS2-GFP (A II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (A III) and a 3D surface plot of the raw data (A IV). (B I–B IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (B I) and FLS2-GFP (B II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (B III) and a 3D surface plot of the raw data (B IV). (C I–C IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (C I) and BRI1-GFP (C II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (C III) and a 3D surface plot of the raw data (C IV). (D I–D IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (D I) and BRI1-GFP (D II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (D III) and a 3D surface plot of the raw data (D IV). (E I–E IV) Confocal micrographs of TUB5-mCherry (E I) and FLS2-GFP (E II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (E III) and a 3D surface plot of the raw data (E IV). (F I–F IV) Confocal micrographs of TUA6-GFP (F I) and FLS2-mCherry (F II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (F III) and a 3D surface plot of the raw data (F IV). (G I–G IV) Confocal micrographs of TUB5-mCherry (G I) and BRI1-GFP (G II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (G III) and a 3D surface plot of the raw data (G IV). (H I–H IV) Confocal micrographs of TUA6-GFP (H I) and BRI1-mRFP (H II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (H III) and a 3D surface plot of the raw data (H IV). Fluorescence signals of cytoskeleton components are shown in magenta, fluorescence signals of FLS2 or BRI1 receptors are shown in green. The abbreviation tRFP stands for TagRFP. Scale bars represent 5 µm. The image series indicate that FLS2 and BRI1 receptor clusters repeatedly localised on top of actin filaments as indicated by white arrows in the respective 3D surface plots. In contrast, FLS2 and, to a minor extend, BRI1 receptors were largely excluded from plasma membrane areas that co-localised with cortical microtubules as indicated by white arrows in the respective 3D surface plots.DOI:http://dx.doi.org/10.7554/eLife.25114.005
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fig1s2: Plasma membrane localisation of FLS2 and BRI1 with respect to the cytoskeleton.(A I–A IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (A I) and FLS2-GFP (A II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (A III) and a 3D surface plot of the raw data (A IV). (B I–B IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (B I) and FLS2-GFP (B II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (B III) and a 3D surface plot of the raw data (B IV). (C I–C IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (C I) and BRI1-GFP (C II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (C III) and a 3D surface plot of the raw data (C IV). (D I–D IV) Confocal micrographs of actin filaments visualised using LifeAct-tRFP (D I) and BRI1-GFP (D II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (D III) and a 3D surface plot of the raw data (D IV). (E I–E IV) Confocal micrographs of TUB5-mCherry (E I) and FLS2-GFP (E II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (E III) and a 3D surface plot of the raw data (E IV). (F I–F IV) Confocal micrographs of TUA6-GFP (F I) and FLS2-mCherry (F II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (F III) and a 3D surface plot of the raw data (F IV). (G I–G IV) Confocal micrographs of TUB5-mCherry (G I) and BRI1-GFP (G II) in epidermal leaf cells of Arabidopsis seedling cotyledons as well as the merged image (G III) and a 3D surface plot of the raw data (G IV). (H I–H IV) Confocal micrographs of TUA6-GFP (H I) and BRI1-mRFP (H II) after transient co-expression in epidermal leaf cells of N. benthamiana as well as the merged image (H III) and a 3D surface plot of the raw data (H IV). Fluorescence signals of cytoskeleton components are shown in magenta, fluorescence signals of FLS2 or BRI1 receptors are shown in green. The abbreviation tRFP stands for TagRFP. Scale bars represent 5 µm. The image series indicate that FLS2 and BRI1 receptor clusters repeatedly localised on top of actin filaments as indicated by white arrows in the respective 3D surface plots. In contrast, FLS2 and, to a minor extend, BRI1 receptors were largely excluded from plasma membrane areas that co-localised with cortical microtubules as indicated by white arrows in the respective 3D surface plots.DOI:http://dx.doi.org/10.7554/eLife.25114.005
Mentions: In contrast to the highly mobile endomembrane compartments, the visualised FLS2- and BRI1-GFP clusters appeared rather immobile and seemed to follow a certain spatial organisation. FLS2 and BRI1 clusters often aligned in pearl chain-like structures and interconnected lines with low fluorescence intensities frequently separated by PM areas containing several receptor clusters, in particular for FLS2-GFP (Figure 1—figure supplement 2).

View Article: PubMed Central - PubMed

ABSTRACT

Cell surface receptors govern a multitude of signalling pathways in multicellular organisms. In plants, prominent examples are the receptor kinases FLS2 and BRI1, which activate immunity and steroid-mediated growth, respectively. Intriguingly, despite inducing distinct signalling outputs, both receptors employ common downstream signalling components, which exist in plasma membrane (PM)-localised protein complexes. An important question is thus how these receptor complexes maintain signalling specificity. Live-cell imaging revealed that FLS2 and BRI1 form PM nanoclusters. Using single-particle tracking we could discriminate both cluster populations and we observed spatiotemporal separation between immune and growth signalling platforms. This finding was confirmed by visualising FLS2 and BRI1 within distinct PM nanodomains marked by specific remorin proteins and differential co-localisation with the cytoskeleton. Our results thus suggest that signalling specificity between these pathways may be explained by the spatial separation of FLS2 and BRI1 with their associated signalling components within dedicated PM nanodomains.

Doi:: http://dx.doi.org/10.7554/eLife.25114.001

No MeSH data available.


Related in: MedlinePlus