Plant phosphoinositide-dependent phospholipases C: variations around a canonical theme
Igor Pokotylo1, Yaroslav Kolesnikov, Volodymyr Kravets
1Institute of Bioorganic Chemistry and Petrochemistry, NAS of Ukraine, Kiev, Ukraine.
Biochimie
|July 17, 2013
Summary
Plant phosphoinositide-specific phospholipase C (PI-PLC) enzymes, despite simple structures, regulate crucial plant development and stress responses. Their signaling pathways differ from animals, involving unique mediators like phosphatidic acid (PA).
Area of Science:
- Plant biology
- Molecular signaling
- Biochemistry
Background:
- Phosphoinositide-specific phospholipase C (PI-PLC) enzymes hydrolyze phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2) into diacylglycerol (DAG) and inositol triphosphate (IP3) in a Ca(2+)-dependent manner.
- Plant PI-PLCs share structural similarities with animal PI-PLCs (EF-hand, X/Y, C2 domains) but often lack conventional EF-hand domains.
- Despite their simple structure, plant PI-PLCs are vital for plant development and responses to environmental stresses.
Purpose of the Study:
- To investigate the functional differences and similarities between plant and animal PI-PLCs.
- To elucidate the specific signaling mediators and pathways regulated by plant PI-PLCs.
- To identify unanswered questions regarding the cross-talk and coupling mechanisms in plant PI-PLC signaling.
Main Methods:
- Comparative analysis of PI-PLC domain structures between plant and animal species.
- Investigation of soluble and lipid mediators produced by plant PI-PLCs, including inositol phosphates (IP5, IP6) and phosphatidic acid (PA).
- Examination of the role of PI-PLC in calcium homeostasis and cell phosphoproteome.
Main Results:
- Plant PI-PLCs exhibit functional distinctions from animal counterparts, particularly in signaling mediators.
- Active soluble mediators in plants extend beyond IP3 to include inositol pentakisphosphate (IP5) and inositol hexakisphosphate (IP6).
- The primary active lipid mediator in plants appears to be phosphatidic acid (PA), not DAG.
Conclusions:
- Plant PI-PLCs are crucial regulators of plant processes, utilizing distinct signaling molecules compared to animals.
- The interplay between PI-PLC activity and inositol phosphate metabolism is critical for signal transduction.
- Further research is needed to understand the cross-talk between lipid and soluble mediators and the coupling of PI-PLCs with kinases.
Keywords:
ABADAGDAG-kinaseDGKIP(3)IP(5)IP(6)Inositol-phosphateLipid signallingPAPHPIPI-4,5-P(2)PI-4-PPI-PLCPLDPhosphatidic acidPhosphoinositidesPhospholipase CSASUMOabscisic aciddiacylglycerolinositol hexakisphosphateinositol pentakisphosphateinositol triphosphatephosphatidic acidphosphatidylinositolphosphatidylinositol-4,5-bisphosphatephosphatidylinositol-4-phosphatephosphoinositide-dependent phospholipase Cphospholipase Dpleckstrin homologysalicylic acidsmall ubiquitin-like modifierMore Related Videos
Related Concept Videos
Phosphoinositides and PIPs
Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
IP3/DAG Signaling Pathway
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and produces two-second...
Protein Kinases and Phosphatases
Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases
Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Amplifying Signals via Second Messengers
Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
Synthesis of Phosphatidylcholine in the ER Membrane
The ER synthesizes lipids for building cell membranes and performing cellular functions such as energy storage and signaling. The lipid synthesis machinery embedded in the ER membrane primarily collects all reactants from the cytosol. Following synthesis, the secretory pathway and the ER contact sites distribute these lipids to other cellular organelles. Additionally, the energy-rich triacylglycerides are transported from the ER via lipid droplets.
The major components of all eukaryotic cell...
The major components of all eukaryotic cell...


