Kanaho Yasunori, Kobayashi-Nakano Akiko, Yokozeki Takeaki
Department of Physiological Chemistry, Graduate School of Comprehensive Human Sciences, Institute of Basic Medical Sciences, University of Tsukuba, Japan.
Biol Pharm Bull. 2007 Sep;30(9):1605-9. doi: 10.1248/bpb.30.1605.
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.
磷酸肌醇激酶，即磷脂酰肌醇4-磷酸5-激酶（PIP5K），可产生多功能磷脂磷脂酰肌醇4,5-二磷酸（PI4,5P₂），PIP5K通过该物质在多种细胞功能中发挥关键作用。到目前为止，已鉴定出三种PIP5K同工酶和剪接变体。我们推测，由于每种同工酶存在特异性激活剂或招募剂，每种PIP5K同工酶或剪接变体以时空不同的方式被激活：PIP5K这种时空不同的激活在不同时间于细胞的不同区室产生PI4,5P₂，这种现象可能是PI4,5P₂/PIP5K明显具有多种功能的原因。越来越多的证据支持这一观点，即每种PIP5K同工酶由其特异性激活剂激活，并在独特的细胞功能中发挥关键作用。在本文中，我们描述了关于PIP5K同工酶特异性激活机制和生理功能的最新进展。
