Hammond Gerald R V, Schiavo Giampietro, Irvine Robin F
Department of Pharmacology, University of Cambridge, Cambridge, UK.
Biochem J. 2009 Jul 29;422(1):23-35. doi: 10.1042/BJ20090428.
PtdIns4P is the major precursor for the synthesis of the multifunctional plasma membrane lipid, PtdIns(4,5)P(2). Yet PtdIns4P also functions as a regulatory lipid in its own right, particularly at the Golgi apparatus. In the present study we define specific conditions that enable preservation of several organellar membranes for the immunocytochemical detection of PtdIns4P. We report distinct pools of this lipid in both Golgi and plasma membranes, which are synthesized by different PI4K (phosphatidylinositol 4-kinase) activities, and also the presence of PtdIns4P in cytoplasmic vesicles, which are not readily identifiable as PI4K containing trafficking intermediates. In addition, we present evidence that the majority of PtdIns4P resides in the plasma membrane, where it is metabolically distinct from the steady-state plasma membrane pool of PtdIns(4,5)P(2).
磷脂酰肌醇-4-磷酸（PtdIns4P）是合成多功能质膜脂质磷脂酰肌醇-4,5-二磷酸（PtdIns(4,5)P(2)）的主要前体。然而，PtdIns4P本身也作为一种调节性脂质发挥作用，尤其是在高尔基体。在本研究中，我们定义了特定条件，能够保留多种细胞器膜用于PtdIns4P的免疫细胞化学检测。我们报告了在高尔基体和质膜中这种脂质的不同池，它们由不同的磷脂酰肌醇-4-激酶（PI4K）活性合成，并且在细胞质小泡中也存在PtdIns4P，这些小泡不容易被识别为含PI4K的运输中间体。此外，我们提供证据表明，大多数PtdIns4P存在于质膜中，在那里它在代谢上与PtdIns(4,5)P(2)的稳态质膜池不同。
