Regulatory Membrane Lipids
Membranes of eukaryotic cells consist mostly of structural phospholipids. They do however also contain minor amounts of lipids with important regulatory functions. Phosphoinositides (PIs) are an example for such regulatory lipids.
PIs are the phosphorylated derivatives of the phospholipid phosphatidylinositol (PtdIns). The illustration shows a simplified view of the phosphorylation sequence leading from PtdIns to PtdIns 4-phosphate (PtdIns4P) and PtdIns 4,5-bisphosphate (PtdIns(4,5)P2. Beside those shown, other phosphorylations are also possible. PI 4-kinase and PI4P 5-kinase are important key enzymes of PI metabolism. (from Heilmann & Heilmann, Plant Biol. (Stuttg), 2012)
PIs influence biochemical activity or localization of various proteins by acting as ligands to these target proteins. Alternatively, PIs are also precursors for second messengers, such as inositolpolyphosphates (IPPs). The focus of our work is to elucidate the functions of PIs in plants. PIs are studied by combined biochemical and cell biological approaches that include the characterization of relevant enzymes in vitro and in vivo , such as PI-synthases, PI-kinases and in particular also PI4P 5-kinases. Our results so far indicate that PIs are of key importance for development and function of plants and also have roles in the adaptation to environmental stresses. It may be possible that this information will lead to new approaches to modulate plant stress-tolerance in the future.
Details to individual projects are accessible through the following links:
- Phosphoinositides and the control of cellular polarity
- Phosphoinosities and the control of endocytosis and exocytosis
- Regulation of plant PI4P 5-kinases by phosphorylation
- Phosphoinositide-pools and the interaction network of PI4P 5-kinases
- AG Dr. Mareike Heilmann: Nuclear Phosphoinositides
- Regulation of alkaloid metabolism by phospholipids
- New determinants of oil deposition in plants
- Phosphoinositides and plant cell wall deposition