脂滴是胞質(zhì)器,，存儲三酸甘油脂和膽固醇等脂質(zhì),。在營養(yǎng)缺乏條件下,，三酸甘油脂液滴被水解產(chǎn)生自由脂肪酸,，后者被氧化以提供能量,。對于饑餓的第二個細(xì)胞反應(yīng)是細(xì)胞自吞，在這個過程中細(xì)胞消化自己的組成部分來提供營養(yǎng),。
Singh等人介紹了細(xì)胞自吞在調(diào)控脂質(zhì)代謝中的一個新功能,，他們將這種功能稱之為“macrolipophagy”。在這一過程中,，脂滴和自吞組分在饑餓期間結(jié)合在一起,，而細(xì)胞自吞的抑制則會增加脂滴中的脂質(zhì)存儲。自吞作用通過將脂滴釋放給溶酶體去降解來促進(jìn)脂質(zhì)水解和自由脂肪酸的生成,。這項工作發(fā)現(xiàn)了自吞在調(diào)控脂質(zhì)代謝中的一個關(guān)鍵作用,，可能為防止疾病中的脂質(zhì)積累提供一個新途徑。(生物谷Bioon.com)
生物谷推薦原始出處：
Nature 458, 1131-1135 (30 April 2009) | doi:10.1038/nature07976
Autophagy regulates lipid metabolism
Rajat Singh1,2,7, Susmita Kaushik1,2,3,4,7, Yongjun Wang1,2, Youqing Xiang1,2, Inna Novak2,5, Masaaki Komatsu6, Keiji Tanaka6, Ana Maria Cuervo1,2,3,4 & Mark J. Czaja1,2
1 Department of Medicine,
2 The Marion Bessin Liver Research Center,
3 Department of Developmental and Molecular Biology,
4 Institute for Aging Studies,
5 Department of Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
6 Laboratory of Frontier Science, Tokyo Metropolitan Institute of Medical Science, Bunkyo-ku, Tokyo 113-8613, Japan
7 These authors contributed equally to this work.
The intracellular storage and utilization of lipids are critical to maintain cellular energy homeostasis. During nutrient deprivation, cellular lipids stored as triglycerides in lipid droplets are hydrolysed into fatty acids for energy. A second cellular response to starvation is the induction of autophagy, which delivers intracellular proteins and organelles sequestered in double-membrane vesicles (autophagosomes) to lysosomes for degradation and use as an energy source. Lipolysis and autophagy share similarities in regulation and function but are not known to be interrelated. Here we show a previously unknown function for autophagy in regulating intracellular lipid stores (macrolipophagy). Lipid droplets and autophagic components associated during nutrient deprivation, and inhibition of autophagy in cultured hepatocytes and mouse liver increased triglyceride storage in lipid droplets. This study identifies a critical function for autophagy in lipid metabolism that could have important implications for human diseases with lipid over-accumulation such as those that comprise the metabolic syndrome.
