Expression of the CD36 homolog (FAT) in fibroblast cells: Effects on fatty acid transport
Expression of the CD36 homolog (FAT) in fibroblast cells: Effects on fatty acid transport
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DOI：
10.1073/pnas.93.7.2646
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发表时间：
1996-04-02
影响因子：
11.1
通讯作者：
Abumrad, NA
中科院分区：
文献类型：
--
作者：
Ibrahimi, A;Sfeir, Z;Abumrad, NA
脂肪细胞膜糖蛋白（FAT）与人CD 36同源，以前曾参与长链脂肪酸的结合/转运。它结合长链脂肪酸的反应性衍生物，结合是特异性的，并与脂肪酸摄取的显著抑制相关。该蛋白的组织分布及其表达的调节也与其假定的作用一致。在这份报告中，我们研究了FAT表达对缺乏该蛋白的Ob 17 PY成纤维细胞摄取脂肪酸的速率和性质的影响。基于FAT mRNA和蛋白质水平选择P21、P22和P25。可以用抗CD 36抗体FITC-OKM 5证明细胞表面标记。与此一致，免疫反应性FAT的主要部分与质膜部分相关。与用空载体转染的细胞相比，油酸盐和/或棕榈酸盐摄取的测定证明了三种表达FAT的克隆中的较高速率，克隆P21在蛋白质印迹上具有最高的蛋白质水平，表现出转运速率的最大增加。脂肪酸在表达脂肪酸的P21细胞中的摄取反映了两种成分，一种是K-m为0.004 μ M的根皮素敏感的高亲和力饱和成分，另一种是未结合脂肪酸的线性函数的基础根皮素不敏感成分，P21细胞将更多的外源脂肪酸掺入磷脂中，表明脂肪酸的结合之后是它们转移到细胞中，并且这两个过程都被FAT表达增加，这些数据支持FAT/CD 36作为长链脂肪酸的高亲和力膜受体/转运蛋白的解释。
An adipocyte membrane glycoprotein, (FAT), homologous to human CD36, has been previously implicated in the binding/transport of long-chain fatty acids, It bound reactive derivatives of long-chain fatty acids and binding was specific and associated with significant inhibition of fatty acid uptake. Tissue distribution of the protein and regulation of its expression were also consistent with its postulated role, In this report, we have examined the effects of FAT expression on rates and properties of fatty acid uptake by Ob17PY fibroblasts lacking the protein, Three clones (P21, P22, and P25) were selected based on FAT mRNA and protein levels, Cell surface labeling could be demonstrated with the anti-CD36 antibody FITC-OKM5. In line with this, the major fraction of immunoreactive FAT was associated with the plasma membrane fraction, Assays of oleate and/or palmitate uptake demonstrated higher rates in the three FAT-expressing clones, compared to cells transfected with the empty vector, Clone P21, which had the highest protein levels on Western blots, exhibited the largest increase in transport rates. Fatty acid uptake in FAT-expressing P21 cells reflected two components, a phloretin-sensitive high-affinity saturable component with a K-m of 0.004 mu M and a basal phloretin-insensitive component that was a linear function of unbound fatty acid, P21 cells incorporated more exogenous fatty acid into phospholipids, indicating that binding of fatty acids was followed by their transfer into the cell and that both processes were increased by FAT expression, The data support the interpretation that FAT/CD36 functions as a high-affinity membrane receptor/transporter for long-chain fatty acids.