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，我们对 HCT-15 细胞中的 Na^+ 依赖性甘油转运蛋白进行了研究，特别检查了 1）丁酸盐处理诱导的细胞分化和 2）结构上的几种化合物对甘油摄取的影响。与甘油类似。丁酸盐处理使最大甘油转运速率增加约 5 倍，而不会显着改变丁酸盐处理的甘油摄取。细胞是高度Na^+依赖性的，并且与未处理的细胞中一样被一些结构类似的化合物特异性抑制，表明Na^+依赖性甘油转运蛋白的诱导。此外，这种诱导几乎完全被放线菌素D（一种抑制剂）抑制。基因转录的抑制剂和蛋白质合成抑制剂放线菌酮，所有这些发现都为甘油的特定转运蛋白的存在提供了证据。在七种化合物中测试了其对甘油的抑制作用。甘油摄取，甘油衍生物的酯型单醋精和单丁酸甘油酯被发现是最有效的抑制剂，因为它们竞争性地抑制甘油摄取，因此它们可能是甘油转运蛋白的底物。不同意可能是通过转运蛋白传递的，但发现 1, 2-丙二醇具有竞争性抑制作用，尽管相对较弱，其中S-(+)-对映异构体比 R-(-)-对映异构体更受转运蛋白青睐。所有这些特征也是特定转运蛋白介导的转运的特征，为甘油的这种特定转运蛋白的存在提供了证据。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种证据，这将有助于识别它并阐明其转运机制和生理作用。