Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia.
Cells. 2023 May 17;12(10):1411. doi: 10.3390/cells12101411.
Phosphoinositides (PIs) are small, phosphorylated lipids that serve many functions in the cell. They regulate endo- and exocytosis, vesicular trafficking, actin reorganization, and cell mobility, and they act as signaling molecules. The most abundant PIs in the cell are phosphatidylinositol-4-monophosphate (PI4P) and phosphatidylinositol-4,5-bisphosphate [PI(4,5)P]. PI4P is mostly localized at the Golgi apparatus where it regulates the anterograde trafficking from the Golgi apparatus to the plasma membrane (PM), but it also localizes at the PM. On the other hand, the main localization site of PI(4,5)P is the PM where it regulates the formation of endocytic vesicles. The levels of PIs are regulated by many kinases and phosphatases. Four main kinases phosphorylate the precursor molecule phosphatidylinositol into PI4P, divided into two classes (PI4KIIα, PI4KIIβ, PI4KIIIα, and PI4KIIIβ), and three main kinases phosphorylate PI4P to form PI(4,5)P (PI4P5KIα, PI4P5KIβ, and PI4P5KIγ). In this review, we discuss the localization and function of the kinases that produce PI4P and PI(4,5)P, as well as the localization and function of their product molecules with an overview of tools for the detection of these PIs.
磷酸肌醇（PIs）是一种小的、磷酸化的脂质，在细胞中具有多种功能。它们调节内吞和胞吐作用、囊泡运输、肌动蛋白重组和细胞迁移，并作为信号分子发挥作用。细胞中最丰富的 PIs 是磷脂酰肌醇-4-单磷酸（PI4P）和磷脂酰肌醇-4,5-二磷酸[PI（4,5）P]。PI4P 主要定位于高尔基体，在那里它调节从高尔基体到质膜（PM）的正向运输，但它也定位于 PM。另一方面，PI（4,5）P 的主要定位部位是 PM，在那里它调节内吞小泡的形成。PIs 的水平受许多激酶和磷酸酶的调节。四种主要的激酶将前体分子磷脂酰肌醇磷酸化为 PI4P，分为两类（PI4KIIα、PI4KIIβ、PI4KIIIα 和 PI4KIIIβ），三种主要的激酶将 PI4P 磷酸化为 PI（4,5）P（PI4P5KIα、PI4P5KIβ 和 PI4P5KIγ）。在这篇综述中，我们讨论了产生 PI4P 和 PI（4,5）P 的激酶的定位和功能，以及它们的产物分子的定位和功能，并概述了这些 PIs 的检测工具。
