6月21日，Science在线报道了人类对磷酸肌醇4磷酸盐（PI4P）在细胞质膜中重要作用的新认识。
磷脂酰环己六醇（4,5）- 二磷酸[PI（4,5）P2]是细胞质膜（PM）中一种含量很少的磷脂。但它却可行使许多细胞质膜（PM）的功能。而其合成的前体，磷酸肌醇4磷酸盐（PI4P），除了合成PI（4,5）P2以外，此前却没有被发现具有其他PM功能。
研究者将药理和化学遗传学方法相结合，探索PM中PI4P的功能。研究意外发现，在细胞PM中， PI4P具有一些新的重要作用：最重要的是这种功能不依赖于其合成PI（4,5）P2的功能。相反，PI4P自主性地与PI（4,5）P2一道支持构成细胞PM的阴离子脂质池。
研究者认为，只需要多价阴离子脂质的配合，PI4P即可满足任何PM功能。这使得PI（4,5）P2可自由进行快速周转并调节其大量的特异性效应蛋白。由于PI（4,5）P2的快速周转可能会降低其有效浓度，PI4P的支持无疑保证了PM的独特静电性能的稳定性。
这一发现，加深了人类对细胞质膜PI4P功能的认识。对细胞膜相关疾病的研究和治疗都有重要意义。（生物谷bioon.com）
doi:10.1016/j.cell.2011.10.017
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PI4P and PI(4,5)P2 Are Essential But Independent Lipid Determinants of Membrane Identity
Gerald R. V. Hammond1,3,*, Michael J Fischer1, Karen E Anderson2, Jon Holdich1, Ardita Koteci1, Tamas Balla3, Robin F. Irvine1,*
The quantitatively minor phospholipid phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] fulfils many cellular functions in the plasma membrane (PM), whereas its synthetic precursor, phosphatidylinositol 4-phosphate (PI4P), has no assigned PM roles apart from PI(4,5)P2 synthesis. We used a combination of pharmacological and chemical genetic approaches to probe the function of PM PI4P, most of which was not required for the synthesis or functions of PI(4,5)P2. However, depletion of both lipids was required to prevent PM targeting of proteins that interact with acidic lipids or activation of the transient receptor potential vanilloid 1 cation channel. Therefore, PI4P contributes to the pool of polyanionic lipids that define plasma membrane identity and to some functions previously attributed specifically to PI(4,5)P2, which may be fulfilled by a more general polyanionic lipid requirement
