Plasma membrane cholesterol is a key molecule in shear stress-dependent activation of extracellular signal-regulated kinase
Plasma membrane cholesterol is a key molecule in shear stress-dependent activation of extracellular signal-regulated kinase
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DOI：
10.1074/jbc.273.48.32304
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发表时间：
1998-11-27
影响因子：
4.8
通讯作者：
Jo, H
中科院分区：
文献类型：
--
作者：
Park, H;Go, YM;Jo, H
剪切应力，即流体产生的拖曳力，差异性地激活牛主动脉内皮细胞（BAEC）中的细胞外信号调节激酶（ERK）和c-Jun NH 2-末端激酶（JNK）（Jo，H.，Yoga，IL. M，Law，R，Rong，J.，和McDonald，J.M.（1997）J.Biol.Chem.272，1395-1401）。在这里，我们研究是否在质膜胆固醇eniched舱室负责这种差异调节。用胆固醇结合抗生素filipin预处理BAEC，不能抑制JNK的剪切依赖性激活。相反，filipin和其他膜渗透性胆固醇结合剂（毛地黄皂苷和制霉菌素），而不是脂质结合剂甲苯噻嗪，抑制ERK的剪切依赖性激活。胆固醇结合药物的作用似乎不是由于膜透化，因为用去污剂处理BAEC，Triton X-100也渗透膜，不抑制剪切依赖性激活ERK。此外，剪切依赖性激活的ERK，而不是JNK，抑制环糊精，膜不可渗透的胆固醇结合剂，它去除细胞表面的胆固醇。此外，环糊精的影响，防止在孵育过程中加入胆固醇。这些结果表明，在细胞膜中的胆固醇或胆固醇敏感隔室发挥选择性和重要的作用，在激活ERK，但不是JNK的剪切应力。尽管暴露于剪切应力（1小时）使小窝的数量增加3倍，但用菲律宾肽处理在对照或剪切暴露的细胞中均没有影响，这表明小窝密度本身不是剪切依赖性ERK激活的关键决定因素。总之，当前研究表明质膜中的胆固醇敏感性微区，如小窝样区，在剪切应力对ERK和JNK的差异激活中起关键作用。
Shear stress, the dragging force generated by fluid now, differentially activates extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) in bovine aortic endothelial cells (BAEC) (Jo, H., Sipos, IL, Go, Y. M, Law, R, Rong, J., and McDonald, J.M. (1997) J. Biol. Chem. 272, 1395-1401). Here, we examine whether cholesterol-enniched compartments in the plasma membrane are responsible for such differential regulation. Pretreatment of BAEC with a cholesterol-binding antibiotic, filipin, did not inhibit shear-dependent activation of JNK In contrast, filipin and other membrane-permeable cholesterol-binding agents (digitonin and nystatin), but not the lipid-binding agent xylazine, inhibited shear-dependent activation of ERK The effect of cholesterol-binding drugs did not appear to be due to membrane permeabilization, since treatment of BAEC with a detergent, Triton X-100 which also permeabilizes membranes, did not inhibit shear-dependent activation of ERK. Furthermore, shear-dependent activation of ERK but not JNK, was inhibited by cyclodextrin, a membrane-impermeable cholesterol-binding agent, which removes cell-surface cholesterol Moreover, the effects of cyclodextrin were prevented by adding cholesterol during the incubation. These results indicate that cholesterol or cholesterol-sensitive compartments in the plasma membrane play a selective and essential role in activation of ERK but not JNK by shear stress. Although exposure to shear stress (1 h) increased the number of caveolae by 3-fold, treatment with filipin had no effect in either control or shear-exposed cells suggesting that caveolae density per se is not a crucial determinant in shear-dependent ERK activation In summary, the current study suggests that cholesterol-sensitive microdomains in the plasma membrane, such as caveolae-like domains,play a critical role in differential activation of ERK and JNK by shear stress.