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Arabidopsis AtPLC2 Is a Primary Phosphoinositide-Specific Phospholipase C in Phosphoinositide Metabolism and the Endoplasmic Reticulum Stress Response.

Kanehara K, Yu CY, Cho Y, Cheong WF, Torta F, Shui G, Wenk MR, Nakamura Y - PLoS Genet. (2015)

Bottom Line: The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth.Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles.Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan; Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Graduate Institute of Biotechnology and Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan; Muroran Institute of Technology, Muroran, Japan.

ABSTRACT
Phosphoinositides represent important lipid signals in the plant development and stress response. However, multiple isoforms of the phosphoinositide biosynthetic genes hamper our understanding of the pivotal enzymes in each step of the pathway as well as their roles in plant growth and development. Here, we report that phosphoinositide-specific phospholipase C2 (AtPLC2) is the primary phospholipase in phosphoinositide metabolism and is involved in seedling growth and the endoplasmic reticulum (ER) stress responses in Arabidopsis thaliana. Lipidomic profiling of multiple plc mutants showed that the plc2-1 mutant increased levels of its substrates phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, suggesting that the major phosphoinositide metabolic pathway is impaired. AtPLC2 displayed a distinct tissue expression pattern and localized at the plasma membrane in different cell types, where phosphoinositide signaling occurs. The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth. Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles. Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

No MeSH data available.


Lipidomic profiling of phosphoinositide levels in 14-day-old seedlings of the plc1-1, plc2-1, plc3-1, plc4-1, plc6-1 mutants compared with the wild type (WT).(A) Phosphatidylinositol 4-phosphate (PI4P), (B) phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], (C) sum of phosphatidylinositol 3-phosphate (PI3P) and phosphatidylinositol 5-phosphate (PI5P), (D) phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]. Data are mean±SD of 4 biological replicates. **P<0.01, ***P<0.001 (by Student’s t-test).
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pgen.1005511.g003: Lipidomic profiling of phosphoinositide levels in 14-day-old seedlings of the plc1-1, plc2-1, plc3-1, plc4-1, plc6-1 mutants compared with the wild type (WT).(A) Phosphatidylinositol 4-phosphate (PI4P), (B) phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], (C) sum of phosphatidylinositol 3-phosphate (PI3P) and phosphatidylinositol 5-phosphate (PI5P), (D) phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]. Data are mean±SD of 4 biological replicates. **P<0.01, ***P<0.001 (by Student’s t-test).

Mentions: To investigate which AtPLC isoform has major contribution to the phosphoinositide metabolism, we performed lipidomic analysis and quantified the phosphoinositide levels of the AtPLC mutants (Fig 3). Among the five AtPLC mutants isolated, only the plc2-1 mutant showed a 2.5-fold increase in level of phosphatidylinositol 4-phosphate (PI4P) (Fig 3A) and a 1.8-fold increase in that of PI(4,5)P2 (Fig 3B). The sum of phosphatidylinositol 3-phosphate (PI3P) and phosphatidylinositol 5-phosphate (PI5P) levels showed a slight but significant decrease in the plc2-1 mutant (Fig 3C). However, phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] levels (Fig 3D) were not altered in any of these mutants. Because PI4P is a precursor of PI(4,5)P2, an increase in levels of both PI(4,5)P2 and PI4P suggests that a major pathway of PI(4,5)P2 hydrolysis is impaired in the plc2-1 mutant.


Arabidopsis AtPLC2 Is a Primary Phosphoinositide-Specific Phospholipase C in Phosphoinositide Metabolism and the Endoplasmic Reticulum Stress Response.

Kanehara K, Yu CY, Cho Y, Cheong WF, Torta F, Shui G, Wenk MR, Nakamura Y - PLoS Genet. (2015)

Lipidomic profiling of phosphoinositide levels in 14-day-old seedlings of the plc1-1, plc2-1, plc3-1, plc4-1, plc6-1 mutants compared with the wild type (WT).(A) Phosphatidylinositol 4-phosphate (PI4P), (B) phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], (C) sum of phosphatidylinositol 3-phosphate (PI3P) and phosphatidylinositol 5-phosphate (PI5P), (D) phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]. Data are mean±SD of 4 biological replicates. **P<0.01, ***P<0.001 (by Student’s t-test).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581737&req=5

pgen.1005511.g003: Lipidomic profiling of phosphoinositide levels in 14-day-old seedlings of the plc1-1, plc2-1, plc3-1, plc4-1, plc6-1 mutants compared with the wild type (WT).(A) Phosphatidylinositol 4-phosphate (PI4P), (B) phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], (C) sum of phosphatidylinositol 3-phosphate (PI3P) and phosphatidylinositol 5-phosphate (PI5P), (D) phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]. Data are mean±SD of 4 biological replicates. **P<0.01, ***P<0.001 (by Student’s t-test).
Mentions: To investigate which AtPLC isoform has major contribution to the phosphoinositide metabolism, we performed lipidomic analysis and quantified the phosphoinositide levels of the AtPLC mutants (Fig 3). Among the five AtPLC mutants isolated, only the plc2-1 mutant showed a 2.5-fold increase in level of phosphatidylinositol 4-phosphate (PI4P) (Fig 3A) and a 1.8-fold increase in that of PI(4,5)P2 (Fig 3B). The sum of phosphatidylinositol 3-phosphate (PI3P) and phosphatidylinositol 5-phosphate (PI5P) levels showed a slight but significant decrease in the plc2-1 mutant (Fig 3C). However, phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] levels (Fig 3D) were not altered in any of these mutants. Because PI4P is a precursor of PI(4,5)P2, an increase in levels of both PI(4,5)P2 and PI4P suggests that a major pathway of PI(4,5)P2 hydrolysis is impaired in the plc2-1 mutant.

Bottom Line: The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth.Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles.Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan; Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan; Graduate Institute of Biotechnology and Department of Life Sciences, National Chung-Hsing University, Taichung, Taiwan; Muroran Institute of Technology, Muroran, Japan.

ABSTRACT
Phosphoinositides represent important lipid signals in the plant development and stress response. However, multiple isoforms of the phosphoinositide biosynthetic genes hamper our understanding of the pivotal enzymes in each step of the pathway as well as their roles in plant growth and development. Here, we report that phosphoinositide-specific phospholipase C2 (AtPLC2) is the primary phospholipase in phosphoinositide metabolism and is involved in seedling growth and the endoplasmic reticulum (ER) stress responses in Arabidopsis thaliana. Lipidomic profiling of multiple plc mutants showed that the plc2-1 mutant increased levels of its substrates phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, suggesting that the major phosphoinositide metabolic pathway is impaired. AtPLC2 displayed a distinct tissue expression pattern and localized at the plasma membrane in different cell types, where phosphoinositide signaling occurs. The seedlings of plc2-1 mutant showed growth defect that was complemented by heterologous expression of AtPLC2, suggesting that phosphoinositide-specific phospholipase C activity borne by AtPLC2 is required for seedling growth. Moreover, the plc2-1 mutant showed hypersensitive response to ER stress as evidenced by changes in relevant phenotypes and gene expression profiles. Our results revealed the primary enzyme in phosphoinositide metabolism, its involvement in seedling growth and an emerging link between phosphoinositide and the ER stress response.

No MeSH data available.