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The BEACH Domain Protein SPIRRIG Is Essential for Arabidopsis Salt Stress Tolerance and Functions as a Regulator of Transcript Stabilization and Localization.

Steffens A, Bräutigam A, Jakoby M, Hülskamp M - PLoS Biol. (2015)

Bottom Line: Transcriptome-wide analysis revealed qualitative differences in the salt stress-regulated transcriptional response of Col-0 and spi.We show that SPI regulates the salt stress-dependent post-transcriptional stabilization, cytoplasmic agglomeration, and localization to P-bodies of a subset of salt stress-regulated mRNAs.Finally, we show that the PH-BEACH domains of SPI and its human homolog FAN (Factor Associated with Neutral sphingomyelinase activation) interact with DCP1 isoforms from plants, mammals, and yeast, suggesting the evolutionary conservation of an association of BDCPs and P-bodies.

View Article: PubMed Central - PubMed

Affiliation: Botanical Institute, Biocenter, Cologne University, Cologne, Germany.

ABSTRACT
Members of the highly conserved class of BEACH domain containing proteins (BDCPs) have been established as broad facilitators of protein-protein interactions and membrane dynamics in the context of human diseases like albinism, bleeding diathesis, impaired cellular immunity, cancer predisposition, and neurological dysfunctions. Also, the Arabidopsis thaliana BDCP SPIRRIG (SPI) is important for membrane integrity, as spi mutants exhibit split vacuoles. In this work, we report a novel molecular function of the BDCP SPI in ribonucleoprotein particle formation. We show that SPI interacts with the P-body core component DECAPPING PROTEIN 1 (DCP1), associates to mRNA processing bodies (P-bodies), and regulates their assembly upon salt stress. The finding that spi mutants exhibit salt hypersensitivity suggests that the local function of SPI at P-bodies is of biological relevance. Transcriptome-wide analysis revealed qualitative differences in the salt stress-regulated transcriptional response of Col-0 and spi. We show that SPI regulates the salt stress-dependent post-transcriptional stabilization, cytoplasmic agglomeration, and localization to P-bodies of a subset of salt stress-regulated mRNAs. Finally, we show that the PH-BEACH domains of SPI and its human homolog FAN (Factor Associated with Neutral sphingomyelinase activation) interact with DCP1 isoforms from plants, mammals, and yeast, suggesting the evolutionary conservation of an association of BDCPs and P-bodies.

No MeSH data available.


Related in: MedlinePlus

mRNAs of RD29B and TZF3 form cytoplasmic granules.16BoxB-gRD29B (A) and 16BoxB-gTZF3 (B) are indirectly visualized by the LambdaN22-VENUS reporter in transiently transfected leaf epidermis cells (related to Tables 3 and 4). Column I presents the LambdaN22-mVENUS reporter, column II DCP1-mCHERRY, column III the overlay of column I (green) and II (magenta). Rectangular image magnifications present P-bodies nonoverlapping (white arrowheads) and P-bodies overlapping (yellow arrowheads) RNA accumulations. Scale bar: 25 μm.
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pbio.1002188.g009: mRNAs of RD29B and TZF3 form cytoplasmic granules.16BoxB-gRD29B (A) and 16BoxB-gTZF3 (B) are indirectly visualized by the LambdaN22-VENUS reporter in transiently transfected leaf epidermis cells (related to Tables 3 and 4). Column I presents the LambdaN22-mVENUS reporter, column II DCP1-mCHERRY, column III the overlay of column I (green) and II (magenta). Rectangular image magnifications present P-bodies nonoverlapping (white arrowheads) and P-bodies overlapping (yellow arrowheads) RNA accumulations. Scale bar: 25 μm.

Mentions: In cells coexpressing 16BoxB-gTZF3 or 16BoxB-gRD29, we observed accumulations of the reporter constructs in cytoplasmic dot-like structures, indicating that these accumulations are caused by the presence of the 16BoxB-fused target mRNAs (S11A and S11B Fig). Colocalization studies with DCP1, C-terminally fused to mCHERRY, revealed that several mRNA positive accumulations overlap with P-bodies (Fig 9). As P-body and mRNA granule formation follow the principles of classical liquid–liquid phase separations, comprising multivalent and low affinity interactions between proteins constituents and mRNA substrates involved [57–59], their assembly is highly dynamic. As a consequence, the number of mRNA granules and their size is highly variable from cell to cell [39,46,60,61]. This was also observed in our study; however, a quantitative analysis revealed clear differences between nontreated and salt stress-treated samples. In transfected Col-0 cells, 33% of RD29B and 52% of TZF3 positive dots colocalized with P-bodies under nonstress conditions. Their amount in cells treated with 140mM NaCl increased to 57% and 81%, respectively (Table 3).


The BEACH Domain Protein SPIRRIG Is Essential for Arabidopsis Salt Stress Tolerance and Functions as a Regulator of Transcript Stabilization and Localization.

Steffens A, Bräutigam A, Jakoby M, Hülskamp M - PLoS Biol. (2015)

mRNAs of RD29B and TZF3 form cytoplasmic granules.16BoxB-gRD29B (A) and 16BoxB-gTZF3 (B) are indirectly visualized by the LambdaN22-VENUS reporter in transiently transfected leaf epidermis cells (related to Tables 3 and 4). Column I presents the LambdaN22-mVENUS reporter, column II DCP1-mCHERRY, column III the overlay of column I (green) and II (magenta). Rectangular image magnifications present P-bodies nonoverlapping (white arrowheads) and P-bodies overlapping (yellow arrowheads) RNA accumulations. Scale bar: 25 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4489804&req=5

pbio.1002188.g009: mRNAs of RD29B and TZF3 form cytoplasmic granules.16BoxB-gRD29B (A) and 16BoxB-gTZF3 (B) are indirectly visualized by the LambdaN22-VENUS reporter in transiently transfected leaf epidermis cells (related to Tables 3 and 4). Column I presents the LambdaN22-mVENUS reporter, column II DCP1-mCHERRY, column III the overlay of column I (green) and II (magenta). Rectangular image magnifications present P-bodies nonoverlapping (white arrowheads) and P-bodies overlapping (yellow arrowheads) RNA accumulations. Scale bar: 25 μm.
Mentions: In cells coexpressing 16BoxB-gTZF3 or 16BoxB-gRD29, we observed accumulations of the reporter constructs in cytoplasmic dot-like structures, indicating that these accumulations are caused by the presence of the 16BoxB-fused target mRNAs (S11A and S11B Fig). Colocalization studies with DCP1, C-terminally fused to mCHERRY, revealed that several mRNA positive accumulations overlap with P-bodies (Fig 9). As P-body and mRNA granule formation follow the principles of classical liquid–liquid phase separations, comprising multivalent and low affinity interactions between proteins constituents and mRNA substrates involved [57–59], their assembly is highly dynamic. As a consequence, the number of mRNA granules and their size is highly variable from cell to cell [39,46,60,61]. This was also observed in our study; however, a quantitative analysis revealed clear differences between nontreated and salt stress-treated samples. In transfected Col-0 cells, 33% of RD29B and 52% of TZF3 positive dots colocalized with P-bodies under nonstress conditions. Their amount in cells treated with 140mM NaCl increased to 57% and 81%, respectively (Table 3).

Bottom Line: Transcriptome-wide analysis revealed qualitative differences in the salt stress-regulated transcriptional response of Col-0 and spi.We show that SPI regulates the salt stress-dependent post-transcriptional stabilization, cytoplasmic agglomeration, and localization to P-bodies of a subset of salt stress-regulated mRNAs.Finally, we show that the PH-BEACH domains of SPI and its human homolog FAN (Factor Associated with Neutral sphingomyelinase activation) interact with DCP1 isoforms from plants, mammals, and yeast, suggesting the evolutionary conservation of an association of BDCPs and P-bodies.

View Article: PubMed Central - PubMed

Affiliation: Botanical Institute, Biocenter, Cologne University, Cologne, Germany.

ABSTRACT
Members of the highly conserved class of BEACH domain containing proteins (BDCPs) have been established as broad facilitators of protein-protein interactions and membrane dynamics in the context of human diseases like albinism, bleeding diathesis, impaired cellular immunity, cancer predisposition, and neurological dysfunctions. Also, the Arabidopsis thaliana BDCP SPIRRIG (SPI) is important for membrane integrity, as spi mutants exhibit split vacuoles. In this work, we report a novel molecular function of the BDCP SPI in ribonucleoprotein particle formation. We show that SPI interacts with the P-body core component DECAPPING PROTEIN 1 (DCP1), associates to mRNA processing bodies (P-bodies), and regulates their assembly upon salt stress. The finding that spi mutants exhibit salt hypersensitivity suggests that the local function of SPI at P-bodies is of biological relevance. Transcriptome-wide analysis revealed qualitative differences in the salt stress-regulated transcriptional response of Col-0 and spi. We show that SPI regulates the salt stress-dependent post-transcriptional stabilization, cytoplasmic agglomeration, and localization to P-bodies of a subset of salt stress-regulated mRNAs. Finally, we show that the PH-BEACH domains of SPI and its human homolog FAN (Factor Associated with Neutral sphingomyelinase activation) interact with DCP1 isoforms from plants, mammals, and yeast, suggesting the evolutionary conservation of an association of BDCPs and P-bodies.

No MeSH data available.


Related in: MedlinePlus