VA Palo Alto Health Care System, Palo Alto, CA 94304, USA.
Mol Cell Endocrinol. 2013 May 22;371(1-2):15-9. doi: 10.1016/j.mce.2012.10.012. Epub 2012 Oct 23.
Intracellular lipid droplets (LDs) are dynamic organelles that contain a number of associated proteins including perilipin (Plin) and vimentin. Cholesteryl ester (CE)-rich LDs normally accumulate in steroidogenic cells and their mobilization is the preferred initial source of cholesterol for steroidogenesis. Plin1a, 1b and 5 were found to preferentially associate with triacylglycerol-rich LDs and Plin1c and Plin4 to associate with CE-rich LDs, but the biological significance of this remains unanswered. Vimentin null mice were found to have decreased ACTH-stimulated corticosterone levels, and decreased progesterone levels in females, but normal hCG-stimulated testosterone levels in males. Smaller LDs were seen in null cells. Lipoprotein cholesterol delivery to adrenals and ovary was normal, as was the expression of steroidogenic genes; however, the movement of cholesterol to mitochondria was reduced in vimentin null mice. These results suggest that vimentin is important in the maintenance of CE-rich LDs and in the movement of cholesterol for steroidogenesis.
细胞内脂滴 (LDs) 是一种动态细胞器，含有许多相关蛋白，包括脂滴包被蛋白 (Plin) 和波形蛋白。富含胆固醇酯 (CE) 的 LDs 通常在类固醇生成细胞中积累，其动员是类固醇生成的胆固醇的首选初始来源。发现 Plin1a、1b 和 5 优先与富含三酰基甘油的 LDs 结合，而 Plin1c 和 Plin4 与富含 CE 的 LDs 结合，但这一生物学意义仍未得到解答。发现波形蛋白缺失小鼠的 ACTH 刺激的皮质酮水平降低，雌性小鼠的孕激素水平降低，但雄性小鼠的 hCG 刺激的睾酮水平正常。在缺失细胞中观察到较小的 LDs。脂蛋白胆固醇向肾上腺和卵巢的输送正常，类固醇生成基因的表达也正常；然而，胆固醇向线粒体的运动在波形蛋白缺失小鼠中减少。这些结果表明，波形蛋白在维持富含 CE 的 LDs 和胆固醇向类固醇生成的运动中很重要。
