Phosphoinositide kinases are a type of lipid kinases that form phosphoinositides.  Because their products regulate cell life, development, and death, their activity is closely monitored by regulatory proteins, and they can be translocated to produce specific phosphoinositides.  Dysregulation of these enzymes are associated with many human diseases, including cancers, developmental disorders, and immune deficiencies.  Types of phosphoinositide kinases include:

- PI3Ks/type III PI4Ks
- type II PI4Ks
- PIP kinases

Phosphoinositide Kinases

Phosphoinositides are a class of phospholipids that are formed from phosphatidylinositol.  Seven types of phosphoinositides exist:

- phosphatidylinositol 3-phosphate (PI3P)
- phosphatidylinositol 4-phosphate (PI4P)
- phosphatidylinositol 5-phosphate (PI5P)
- phosphatidylinositol 4,5-bisphosphate (PI4,5P2)
- phosphatidylinositol 3,5-bisphosphate (PI3,5P2)
- phosphatidylinositol 3,4-bisphosphate (PI3,4P2)
- phosphatidylinositol 3,4,5-trisphosphate (PIP3)

These molecules collectively make up less than 1% of all lipids, but they function as important mediators of cell growth and development as well as membrane signaling and trafficking.  

Michigan State University

Has a fatty acid in the form of a tail, glycerol head, and a phosphate group. Phospholipids behave uniquely in an aqueous environment they are said to be amphipathic meaning that they have both a hydrophilic head water loving which interacts within the aqueous environment of the cell membrane and a hydrophobic tail water fearing which interacts with the interior of the cell membrane away from the aqueous environment.

Phospholipids

Burke, J. E. (2018). Structural basis for regulation of phosphoinositide kinases and their involvement in human disease. Molecular Cell, 71(5), 653-673.
https://www.sciencedirect.com/science/article/pii/S1097276518306397
doi: 10.1016/j.molcel.2018.08.005

Structural Basis for Regulation
of Phosphoinositide Kinases
and Their Involvement in Human Disease

Phosphoinositides

The amphipathic nature of phospholipids enables them to form uniquely functional structures in aqueous environments. These structures include:

- Micelles
- Lipid bilayer sheets (unit membranes)

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