Liver fatty acid-binding protein targets fatty acids to the nucleus - Real time confocal and multiphoton fluorescence imaging in living cells
Liver fatty acid-binding protein targets fatty acids to the nucleus - Real time confocal and multiphoton fluorescence imaging in living cells
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DOI：
10.1074/jbc.m202923200
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发表时间：
2002-08-09
影响因子：
4.8
通讯作者：
Schroeder, F
中科院分区：
文献类型：
--
作者：
Huang, H;Starodub, O;Schroeder, F
虽然未酯化的长链脂肪酸与过氧化物酶体增殖体激活受体相互作用，启动细胞核内的转录，但关于调节长链脂肪酸向活细胞细胞核分布的因素几乎一无所知。肝脏脂肪酸结合蛋白（LFABP）可能在这一作用中发挥作用的可能性在转染过表达L-FABP的l细胞成纤维细胞中得到了解决，使用了一系列不同链长和不饱和度的荧光脂肪酸。孵育30分钟后，l细胞中检测不到BODIPY-、NBD-和顺式parinaric酸的氧化。同样，l细胞对这些荧光脂肪酸的酯化程度也很低，顺序如下：0% BODIPY-C5， NBD-C6（短链长度）< 0-3% NBD-C18, BODIPY-C16，顺式parinaric酸（长链长度）< 11% BODIPY-C12（中链长度）。实时共聚焦和多光子激光扫描显微镜（CLSM和MPLSM）显示，这些荧光脂肪酸的排列顺序大致如下：长链（BODIPY-C16、NBD-C18）、中链（BODIPY-C12）远多于短链（BODIPY-C5、NBD-C6）。荧光脂肪酸在细胞核中成像，主要与核膜相关，其水平比核外低2-3倍。CLSM和MPLSM表明，L-FABP的表达比活细胞对长链和中链荧光脂肪酸的初始吸收速率和/或平均最大吸收速率提高2-4倍，而对短链荧光脂肪酸没有提高。L-FABP的表达使长链、中链而非短链荧光脂肪酸对细胞核的靶向性提高了2.9 ~ 4.4倍，使中链、长链而非短链荧光脂肪酸的比例（即核与细胞质之比）提高了2 ~ 3.6倍。总之，这些结果首次表明活细胞细胞核中存在未酯化脂肪酸，并表明脂肪酸结合蛋白L-FABP的表达特异性地增强了长链和中链脂肪酸对细胞核的摄取和细胞内靶向。
Although unesterified long chain fatty acids interact with peroxisome proliferator-activated receptors to initiate transcription within the nucleus, almost nothing is known regarding factors regulating long chain fatty acid distribution to the nucleus of living cells. The possibility that the liver fatty acid-binding protein (LFABP) may function in this role was addressed in transfected L-cell fibroblasts overexpressing L-FABP using a series of fluorescent fatty acids differing in chain length and unsaturation. After 30 min of incubation, oxidation of BODIPY-, NBD-, and cis-parinaric acids was undetectable in L-cells. Likewise, L-cells very poorly esterified these fluorescent fatty acids in the following order: 0% BODIPY-C5, NBD-C6 (short chain length) < 0-3% NBD-C18, BODIPY-C16, cis-parinaric acid (long chain length) < 11% BODIPY-C12 (medium chain length). Real time confocal and multiphoton laser scanning microscopy (CLSM and MPLSM) showed that these fluorescent fatty acids were generally taken up in the following order: long chain (BODIPY-C16, NBD-C18) > medium chain (BODIPY-C12) much greater than short chain (BODIPY-C5, NBD-C6). The fluorescent fatty acids were imaged in the nucleus, primarily associated with the nuclear envelope, at levels about 2-3-fold lower than outside the nucleus. CLSM and MPLSM showed that L-FABP expression enhanced by 2-4-fold the initial rate and/or average maximal uptake of the long and medium chain but not the short chain fluorescent fatty acids in living cells. Furthermore, L-FABP expression increased the targeting of long and medium but not short chain fluorescent fatty acids to the nucleus by 2.9-4.4-fold and increased the proportion (i.e. nuclear:cytoplasm ratio) of medium and long chain but not short chain fatty acids by 2-3.6-fold. In summary, these results showed for the first time the presence of unesterified fatty acids in the nucleus of living cells and demonstrated that expression of a fatty acid-binding protein, L-FABP, specifically enhanced uptake and intracellular targeting of long and medium chain fatty acids to the nucleus.