The phosphoinositide kinase PIP5K that produces the versatile signaling phospholipid PI4,5P(2).
The phosphoinositide kinase, phosphatidylinositol 4-phosphate 5-kinase (PIP5K), produces the versatile phospholipid phosphatidylinositol 4,5-bisphosphate (PI4,5P(2)), through which PIP5K plays crucial roles in a wide variety of cell functions. So far, three PIP5K isozymes and splicing variants have been identified. We speculate that each PIP5K isozyme or splicing variant is activated in a tempo-spatially different manner, due to the existence of activators or recruiters specific to each isozyme: this tempo-spatially different activation of PIP5K produces PI4,5P(2) at different compartments of the cell at different times, which phenomenon may be responsible for the apparent multifunction of PI4,5P(2)/PIP5K. Accumulating evidence supports this notion that each PIP5K isozyme is activated by its specific activator and plays a crucial role in a unique cell function. In this article, we describe recent advances regarding the PIP5K isozyme-specific activation mechanisms and physiological functions.
Kanaho
Yasunori
Y
Department of Physiological Chemistry, Graduate School of Comprehensive Human Sciences, Institute of Basic Medical Sciences, University of Tsukuba, Japan. ykanaho@md.tsukuba.ac.jp
Kobayashi-Nakano
Akiko
A
Yokozeki
Takeaki
T
D000818:Animals; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D015778:Minor Histocompatibility Antigens; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000502:physiology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism