Wolfrum C, Buhlmann C, Rolf B, Börchers T, Spener F
Department of Biochemistry, University of Münster, Wilhelm-Klemm Str. 2, D-48149, Münster, Germany.
Biochim Biophys Acta. 1999 Feb 25;1437(2):194-201. doi: 10.1016/s1388-1981(99)00008-6.
The liver-type fatty acid binding protein (L-FABP), a member of a family of mostly cytosolic 14-15 kDa proteins known to bind fatty acids in vitro and in vivo, is discussed to play a role in fatty acid uptake. Cells of the hepatoma HepG2 cell line endogenously express this protein to approximately 0.2% of cytosolic proteins and served as a model to study the effect of L-FABP on fatty acid uptake, by manipulating L-FABP expression in two approaches. First, L-FABP content was more than doubled upon treating the cells with the potent peroxisome proliferators bezafibrate and Wy14,643 and incubation of these cells with [1-14C]oleic acid led to an increase in fatty acid uptake rate from 0.55 to 0.74 and 0.98 nmol/min per mg protein, respectively. In the second approach L-FABP expression was reduced by stable transfection with antisense L-FABP mRNA yielding seven clones with L-FABP contents ranging from 0.03% to 0.14% of cytosolic proteins. This reduction to one sixth of normal L-FABP content reduced the rate of [1-14C]oleic acid uptake from 0.55 to 0. 19 nmol/min per mg protein, i.e., by 66%. The analysis of peroxisome proliferator-treated cells and L-FABP mRNA antisense clones revealed a direct correlation between L-FABP content and fatty acid uptake.
肝型脂肪酸结合蛋白（L-FABP）是一类大多存在于胞质中的14 - 15 kDa蛋白质家族的成员，已知其在体内外均可结合脂肪酸，据认为它在脂肪酸摄取过程中发挥作用。肝癌HepG2细胞系的细胞内源性表达这种蛋白质，其表达量约占胞质蛋白质的0.2%，并作为研究L-FABP对脂肪酸摄取影响的模型，通过两种方法来调控L-FABP的表达。首先，用强效过氧化物酶体增殖剂苯扎贝特和Wy14,643处理细胞后，L-FABP含量增加了一倍多，并且用[1-14C]油酸孵育这些细胞导致脂肪酸摄取率分别从0.55增加到0.74和0.98 nmol/（min·mg蛋白质）。在第二种方法中，通过用反义L-FABP mRNA进行稳定转染来降低L-FABP的表达，得到了7个克隆，其L-FABP含量在胞质蛋白质的0.03%至0.14%之间。这种降低至正常L-FABP含量六分之一的情况，使[1-14C]油酸的摄取率从0.55降至0.19 nmol/（min·mg蛋白质），即降低了66%。对过氧化物酶体增殖剂处理的细胞和L-FABP mRNA反义克隆的分析揭示了L-FABP含量与脂肪酸摄取之间存在直接相关性。
