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Molecular and Functional Characteristics of Glycerol Transporter in HCT-15 Cell Model

HCT-15细胞模型中甘油转运蛋白的分子和功能特征

基本信息

批准号：
18590149
负责人：
YUASA Hiroaki
金额：
$ 2.57万
依托单位：
Nagoya City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

To clarify the molecular and functional characteristics of glycerol transporters, we conducted studies on a Na^+-dependent one in HCT-15 cells, particularly examining the effects on glycerol uptake of 1) cell differentiation induced by butyrate treatment and 2) several compounds structurally analogous to glycerol.Butyrate treatment brought about an approximately 5-fold increase in the maximum glycerol transport rate, without altering the Michaelis constant (affinity) significantly. Glycerol uptake in butyrate-treated cells was highly Na^+-dependent and specifically inhibited by some structurally analogous compounds as it was in untreated cells, indicating an induction of the Na^+-dependent glycerol transporter. Furthermore, this induction was almost completely suppressed by actinomycin D, an inhibitor of gene transcription, and cycloheximide, an inhibitor of protein synthesis. All these findings provide evidences for the presence of a specific transporter protein for glycerol.Among sev … More eral compounds tested for their inhibitory effects on glycerol uptake, monoacetin and monobutyrin, which are ester type of glycerol derivatives, were found to be the most potent inhibitors. Because they inhibited glycerol uptake competitively, they may possibly be substrates of the glycerol transporter. This would suggest that glycerol ester derivatives of drugs might be delivered via the transporter. Interestingly, enantioselective characteristic was found for competitive inhibition, though relatively weak, by 1, 2-propanediol, where the S-(+)-enantiomer is favored by the transporter than the R-(-)-enantiomer. All these features are also characteristic of transport mediated by a specific transporter protein, providing additional evidences for the presence of such a specific transporter protein for glycerol.Thus, we could obtain several lines of evidences for the presence of a Na^+-dependent glycerol transporter in HCT-15 cells. This would help in identifying it and elucidating its transport mechanism and physiological role. Less

为了阐明甘油转运蛋白的分子和功能特征，我们在HCT-15细胞中对Na^+依赖性甘油转运蛋白进行了研究，特别是研究了1）丁酸盐处理诱导的细胞分化和2）几种结构类似于甘油的化合物对甘油摄取的影响。丁酸盐处理使最大甘油转运速率增加约5倍，而不显著改变米氏常数（亲和力）。丁酸盐处理过的细胞对甘油的摄取具有高度的Na^+依赖性，并且与未处理过的细胞一样，某些结构类似的化合物会特异性地抑制甘油的摄取，这表明Na^+依赖性甘油转运蛋白的诱导作用。此外，这种诱导几乎完全抑制放线菌素D，基因转录抑制剂，和放线菌酮，蛋白质合成抑制剂。这些结果为甘油转运蛋白的存在提供了证据。 ...更多信息测试了对甘油摄取的抑制作用的所有化合物，发现甘油衍生物的酯型单乙酸甘油酯和单丁酸甘油酯是最有效的抑制剂。由于它们竞争性地抑制甘油摄取，它们可能是甘油转运蛋白的底物。这表明药物的甘油酯衍生物可能通过转运蛋白传递。有趣的是，发现1，2-丙二醇的竞争性抑制具有对映体选择性特征，尽管相对较弱，其中S-（+）-对映体比R-（-）-对映体更受转运蛋白的青睐。所有这些特征也是由一种特异性的转运蛋白介导的转运的特征，为存在这种特异性的甘油转运蛋白提供了额外的证据，因此，我们可以获得HCT-15细胞中存在Na^+依赖性甘油转运蛋白的多条证据。这将有助于识别它，阐明其运输机制和生理作用。少