Rab1 GTPase promotes expression of beta-adrenergic receptors in rat pulmonary microvascular endothelial cells.
Rab1 GTPase promotes expression of beta-adrenergic receptors in rat pulmonary microvascular endothelial cells.
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DOI：
10.1016/j.biocel.2010.04.009
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发表时间：
2010-07
期刊：
影响因子：
--
通讯作者：
Qian G
中科院分区：
文献类型：
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作者：
Li Y;Wang G;Lin K;Yin H;Zhou C;Liu T;Wu G;Qian G
Rab1在许多细胞中调控β-肾上腺素受体（β-ARs）的表达和功能。然而，这些变化对大鼠肺微血管内皮细胞（RPMVECs）的影响尚不清楚。在本研究中，我们研究了Rab1的作用，Rab1是一种ras样的GTPase，在脂多糖（LPS）存在下，协调蛋白质从内质网（ER）到高尔基体的运输，并调节内源性β-ARs在RPMVECs中的细胞表面靶向和功能。我们发现，慢病毒驱动的野生型Rab1 （Rab1WT）在RPMVECs中的表达强烈增强了细胞表面β-ARs的数量，而显性阴性突变体Rab1N124I则显著减弱了细胞表面β-ARs的表达。此外，LPS刺激显著降低了RPMVECs细胞表面β-ARs的表达；然而，这种作用被野生型Rab1WT过表达逆转。荧光显微镜分析表明，Rab1N124I和Rab1小干扰RNA （siRNA）的表达显著诱导内质网中绿色荧光蛋白（GFP）标记的β2-AR的积累。Rab1WT和Rab1N124I对β- ar介导的细胞外信号调节激酶1/2 （ERK1/2）的激活进行了不同程度的修饰，这与它们对β- ar输出的影响一致。重要的是，Rab1WT的过表达通过增加细胞表面β2-AR的表达，显著降低了lps诱导的rpmvec的超通透性。这些数据表明β-ARs在rpmvec中的功能可以通过调节β-ARs从内质网到高尔基体的流量来调节。我们认为er -to-高尔基转运是调控rpmvec通透性的一个调控位点。
It is known that Rab1 regulates the expression and function of beta-adrenoceptors (β-ARs) in many cells. However, the effect of these changes in rat pulmonary microvascular endothelial cells (RPMVECs) is not known. In the present study, we investigated the role of Rab1, a Ras-like GTPase that coordinates protein transport from the endoplasmic reticulum (ER) to the Golgi body and regulates the cell-surface targeting and function of endogenous β-ARs in RPMVECs in the presence of lipopolysaccharide (LPS). We found that lentivirus-driven expression of wild-type Rab1 (Rab1WT) in RPMVECs strongly enhanced the amount of β-ARs on the cell surface, whereas the dominant-negative mutant Rab1N124I significantly attenuated β-ARs expression on the cell surface. In addition, LPS stimulation significantly reduced β-ARs expression on the cell surface in RPMVECs; however, this effect was reversed by over-expression of wild-type Rab1WT. Fluorescent microscopy analysis demonstrated that expression of Rab1N124I and Rab1 small interfering RNA (siRNA) significantly induced the accumulation of green fluorescent protein (GFP)-tagged β2-AR in the ER. Consistent with their effects on β-ARs export, Rab1WT and Rab1N124I differentially modified the β-AR-mediated activation of extracellular signal-regulated kinase1/2 (ERK1/2). Importantly, over-expression of Rab1WT markedly reduced LPS-induced hyper-permeability of RPMVECs by increasing the expression of β2-AR on the cell surface. These data reveal that β-ARs function in RPMVECs could be modulated by manipulating β-ARs traffic from the ER to the Golgi body. We propose the ER-to-Golgi transport as a regulatory site for control of permeability of RPMVECs.