UPTAKE AND PHOSPHORYLATION OF PHOSPHATIDYLINOSITOL BY RAT-LIVER NUCLEI - ROLE OF PHOSPHATIDYLINOSITOL TRANSFER PROTEIN

被引:52
作者
CAPITANI, S
HELMS, B
MAZZONI, M
PREVIATI, M
BERTAGNOLO, V
WIRTZ, KWA
MANZOLI, FA
机构
[1] UNIV BOLOGNA,I-40126 BOLOGNA,ITALY
[2] STATE UNIV UTRECHT,CTR BIOMEMBRANES & LIPID ENZYMOL,UTRECHT,NETHERLANDS
关键词
(Rat liver nucleus); Phosphatidylinositol; Phosphatidylinositol transfer protein; Phospholipid; Phosphorylation;
D O I
10.1016/0005-2760(90)90303-F
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The incorporation of phosphatidyl[2- 3H]inositol ([3H]PI) from vesicles or microsomal membranes into rat liver nuclei is greatly stimulated by phosphatidylinositol transfer protein (PI-TP). The nuclei are able to phosphorylate [3H]PI, with the production of phosphatidylinositol 4-phosphate (PIP). Recovery of tritiated inositol trisphosphate, inositol phosphate, glycerophosphoinositol and inositol, suggests that in isolated nuclei a large set of enzymes of the PI cycle is present, similar to the enzymes involved in the plasma membrane PI cycle. Incubation with [γ-32P]ATP shows that isolated nuclei are able to phosphorylate endogenous PI to PIP and phosphatidylinositol 4,5-bisphosphate (PIP2). In the presence of exogenous PI and detergent the synthesis of PIP is increased, indicating that in nuclei the PI pool is suboptimal for the PI-kinase activity. The present study suggests that PI-TP may be involved in providing substrates for PI metabolism at the nuclear level. © 1990.
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页码:193 / 200
页数:8
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