Payrastre B, Nievers M, Boonstra J, Breton M, Verkleij A J, Van Bergen en Henegouwen P M
Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
J Biol Chem. 1992 Mar 15;267(8):5078-84.
Several enzymes involved in the phosphoinositide metabolism have been shown to be present in nuclei of rat liver and Friend cells. In this paper we demonstrate that nuclear matrices of mouse NIH 3T3-fibroblasts and rat liver cells, isolated by nuclease treatment and high salt extraction, contain phosphatidylinositol 4-kinase (PdtIns 4-kinase), phosphatidylinositol 4-phosphate 5-kinase (PtdIns(4)P 5-kinase), diacylglycerol kinase, and phospholipase C. By a selective extraction the nucleus can be dissected in the peripheral matrix (lamina-pore complex) and the internal matrix as shown by using marker antibodies. Surprisingly, PtdIns 4-kinase was found exclusively in the peripheral nuclear matrix, whereas PtdIns(4)P 5-kinase was found to be associated to internal matrix structures. Diacylglycerol kinase and phospholipase C activities were also preferentially detected in the internal matrix. These data demonstrate a differential localization of the phosphoinositide kinases in the nucleus and suggest that the phosphoinositide metabolism may play a specific role in the nucleus.
已证实在大鼠肝脏和Friend细胞的细胞核中存在几种参与磷酸肌醇代谢的酶。在本文中,我们证明,经核酸酶处理和高盐提取分离得到的小鼠NIH 3T3成纤维细胞和大鼠肝细胞的核基质含有磷脂酰肌醇4 - 激酶(PdtIns 4 - 激酶)、磷脂酰肌醇4 - 磷酸5 - 激酶(PtdIns(4)P 5 - 激酶)、二酰基甘油激酶和磷脂酶C。通过选择性提取,利用标记抗体显示,细胞核可分为外周核基质(板层孔复合体)和内核基质。令人惊讶的是,仅在外周核基质中发现了PtdIns 4 - 激酶,而PtdIns(4)P 5 - 激酶则与内核基质结构相关。在内核基质中也优先检测到二酰基甘油激酶和磷脂酶C的活性。这些数据证明了磷酸肌醇激酶在细胞核中的差异定位,并表明磷酸肌醇代谢可能在细胞核中发挥特定作用。