Cloning of Rab GTPases expressed in human skeletal muscle: Studies in insulin-resistant subjects
Cloning of Rab GTPases expressed in human skeletal muscle: Studies in insulin-resistant subjects
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DOI：
10.1055/s-2007-978953
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发表时间：
1998-11-01
影响因子：
2.2
通讯作者：
Garvey, WT
中科院分区：
文献类型：
--
作者：
Bao, S;Zhu, J;Garvey, WT
为了探索 Rab GTPases 在人类胰岛素抵抗中的潜在作用，我们首先采用 PCR 克隆方法来鉴定在人类骨骼肌中表达的 Rab 亚型。发现多种 Rab 同工型，包括 Rab1A、Rab4A、Rab5B、Rab7、Rab8、Rab10、Rab12A、Rab13、Rab18、Rab21 和 Rab22 mRNA 在人骨骼肌中表达。第二个目标是检查针对内吞/胞吐区室的 Rab 的 mRNA 表达是否会随着胰岛素抵抗的变化而改变。定量 PCR 分析表明，未患胰岛素抵抗 (IR) 和非胰岛素依赖型糖尿病 (NIDDM) 的患者骨骼肌中 Rab4A、Rab5B 和 Rab18 mRNA 水平与胰岛素敏感对照 (IS) 没有显着差异。在蛋白质水平上，Rab4B 总量在 IS、IR 和 NIDDM 亚组之间没有显着差异。然而，在基底肌中，IR 和 NIDDM 受试者的总膜分数中的 Rab5B 比 IS 受试者高 2.1-3.6 倍。在 IS 受试者中，胰岛素使膜相关 Rab5B 增加了 3 倍，而这种效应在 IR 和 NIDDM 亚组中并不显着。因此，我们首次全面研究了人类肌肉中 Rab 亚型的 mRNA 表达。 Rab GTP 酶的大量表明囊泡运输量大且代谢受到调节。特定 Rab 亚型在胰岛素抵抗中的潜在作用并不依赖于稳态 mRNA 水平的变化，而是通过蛋白质亚细胞分布和运输的改变来证明。
To explore the potential role of Rab GTPases in human insulin resistance, we first employed a PCR-cloning approach to identify Rab isoforms that are expressed in human skeletal muscle. Multiple Rab isoforms including Rab1A, Rab4A, Rab5B, Rab7, Rab8, Rab10, Rab12A, Rab13, Rab18, Rab21, and Rab22 mRNA were found to be expressed in human skeletal muscle. The second goal was to examine whether mRNA expression for Rabs targeted to endocytotic/exocytotic compartments was altered as a function of insulin resistance. Quantitative PCR analysis demonstrated that Rab4A, Rab5B and Rab18 mRNA levels in skeletal muscle from insulin-resistant patients without (IR) and with non-insulin-dependent diabetes mellitus (NIDDM) were not significantly different from those in insulin-sensitive controls (IS). At the protein level, total Rab4B amount was not significantly different among IS, IR and NIDDM subgroups. However, in basal muscle, Rab5B in the total membrane fraction was 2.1-3.6 fold higher in IR and NIDDM than in IS subjects. Insulin increased membrane-associated Rab5B by 3-fold in IS subjects, whereas this effect was not significant in both IR and NIDDM subgroups. Thus, for the first time, we have comprehensively studied the mRNA expression of Rab isoforms in human muscle. The phlethora of Rab GTPases are indicative of high Volume of vesicular traffic and regulated metabolism. The potential role of specific Rab isoforms in insulin resistance does not rely on a change in steady state mRNA levels, but is demonstrable as an alteration in protein subcellular distribution and trafficking.