ACETYL-COA CARBOXYLASE IN REUBER HEPATOMA-CELLS - VARIATION IN ENZYME-ACTIVITY, INSULIN REGULATION, AND CELLULAR LIPID-CONTENT
ACETYL-COA CARBOXYLASE IN REUBER HEPATOMA-CELLS - VARIATION IN ENZYME-ACTIVITY, INSULIN REGULATION, AND CELLULAR LIPID-CONTENT
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DOI：
10.1002/jcb.240480113
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发表时间：
1992-01-01
影响因子：
4
通讯作者：
WITTERS, LA
中科院分区：
文献类型：
--
作者：
BIANCHI, A;EVANS, JL;WITTERS, LA
鲁伯肝癌细胞是研究胰岛素作用、脂类和脂蛋白代谢以及脂肪酸生物合成的限速酶--乙酰辅酶A羧基酶(ACC)的有用细胞系。在对这些细胞的不同克隆系的研究中，我们发现了ACC活性、酶含量和胰岛素调节的显著细胞间差异，与细胞中性脂(甘油三酯)含量的差异平行。对两个不同的无性系FAO和H356A-1进行了详细的研究。这些特征包括ACC活性和酶动力学的差异，肝脏ACC两种主要同工酶(M(R)280,000和265,000 Da)及其异源酶复合体的含量，ACC磷酸化的程度，以及ACC在胰岛素和胰岛素仿生激动剂刺激下被激活的能力。尼罗红染色和荧光激活细胞分选表明，这两株细胞在中性脂含量上也表现出显著的差异，这与ACC活性的基础水平和脂肪酸类似物5-(十四烷氧基)-2-呋喃酸(TOFA)对ACC的抑制有关。这些结果强调了任何特定的鲁伯细胞克隆系对于研究酶调节、底物代谢和激素作用的重要性。在ACC方面，对鲁伯细胞克隆系的对比研究可能为理解无激素和有激素条件下细胞内ACC调节的复杂机制及其在整体肝脂代谢中的调节作用提供有价值的线索(S)。
Reuber hepatoma cells are useful cultured lines for the study of insulin action, lipid and lipoprotein metabolism, and the regulation of acetyl-CoA carboxylase (ACC), the rate-limiting enzyme of fatty acid biosynthesis. During investigations in different clonal lines of these cells, we have uncovered marked intercellular variability in the activity, enzyme content, and insulin regulation of ACC paralleled by differences in cellular neutral lipid (triglyceride) content. Two contrasting clonal lines, Fao and H356A-1, have been studied in detail. Several features distinguish these two lines, including differences in ACC activity and enzyme kinetics, the content of the two major hepatic ACC isozymes (M(r) 280,000 and 265,000 Da) and their heteroisozymic complex, the extent of ACC phosphorylation, and the ability of ACC to be activated on stimulation by insulin and insulinomimetic agonists. As studied by Nile Red staining and fluorescence-activated cell sorting, these two lines also display marked differences in neutral lipid content, which correlates with both basal levels of ACC activity and inhibition of ACC by the fatty acid analog, 5-(tetradecyloxy)-2-furoic acid (TOFA). These results emphasize the importance of characterization of any particular clonal line of Reuber cells for studies of enzyme regulation, substrate metabolism, and hormone action. With respect to ACC, studies in contrasting clonal lines of Reuber cells could provide valuable clues to understanding both the complex mechanisms of intracellular ACC regulation in the absence and presence of hormones and its regulatory role(s) in overall hepatic lipid metabolism.