Abundance and subcellular distribution of MCT1 and MCT4 in heart and fast-twitch skeletal muscles
Abundance and subcellular distribution of MCT1 and MCT4 in heart and fast-twitch skeletal muscles
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DOI：
10.1152/ajpendo.2000.278.6.e1067
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发表时间：
2000-06-01
影响因子：
5.1
通讯作者：
Halestrap, AP
中科院分区：
文献类型：
--
作者：
Bonen, A;Miskovic, D;Halestrap, AP
检测了两种单羧酸转运蛋白（mct）在肌肉和心脏中的表达。MCT1和MCT4蛋白在大鼠骨骼肌中共表达，但只有MCT1在大鼠心脏中表达。在6块大鼠快速收缩肌（红、白腓骨肌、跖、指长伸肌、红、白胫前肌）中，MCT1与MCT4呈负相关（r = -0.94）。MCT1蛋白与MCT1 mRNA相关（r = 0.94）。MCT4 mRNA与MCT4蛋白之间无相关性。MCT1 （r = -0.97）和MCT4 （r = 0.88）蛋白含量与快缩糖酵解纤维百分比相关。当它们的mrna归一化时，MCT1而不是MCT4仍然与大鼠肌肉快速收缩糖酵解纤维组成的百分比相关（r = -0.98）。在质膜（PM）、三联体（TR）、T小管（TT）、肌浆网（SR）和细胞膜（IM）中检测MCT1和MCT4。细胞内有MCT4，但没有MCT1。MCT1亚细胞分布为：PM (100%) > TR (31.6%) > SR (15%) = TT (14%) > IM（1.7%）。MCT4亚细胞分布差异较大[PM (100%) > TR (66.5%) > (36%) = SR (43%) > IM(24%)]。这些研究表明，1)调节MCT1（转录和转录后）和MCT4（转录后）表达的机制不同；2)MCT1和MCT4在肌肉中表达的差异，以及它们在亚细胞位置的差异，表明它们可能在肌肉中具有不同的作用。
The expression of two monocarboxylate transporters (MCTs) was examined in muscle and heart. MCT1 and MCT4 proteins are coexpressed in rat skeletal muscles, but only MCT1 is expressed in rat hearts. Among six rat fast-twitch muscles (red and white gastrocnemius, plantaris, extensor digitorum longus, red and white tibialis anterior) there was an inverse relationship between MCT1 and MCT4 (r = -0.94). MCT1 protein was correlated with MCT1 mRNA (r = 0.94). There was no relationship between MCT4 mRNA and MCT4 protein. MCT1 (r = -0.97) and MCT4 (r = 0.88) protein contents were correlated with percent fast-twitch glycolytic fiber. When normalized for their mRNAs, MCT1 but not MCT4 was still correlated with the percent fast-twitch glycolytic fiber composition of rat muscles (r = -0.98). MCT1 and MCT4 were also measured in plasma membranes (PM), triads (TR), T tubules (TT), sarcoplasmic reticulum (SR), and intracellular membranes (IM). There was an intracellular pool of MCT4 but not of MCT1. The MCT1 subcellular distribution was as follows: PM (100%) > TR (31.6%) > SR (15%) = TT (14%) > IM (1.7%). The MCT4 subcellular distribution was considerably different [PM (100%) > TR (66.5%) > (36%) = SR (43%) > IM (24%)]. These studies have shown that 1) the mechanisms regulating the expression of MCT1 (transcriptional and posttranscriptional) and MCT4 (posttranscriptional) are different and 2) differences in MCT1 and MCT4 expression among muscles, as well as in their subcellular locations, suggest that they may have different roles in muscle.