Clifford G M, Londos C, Kraemer F B, Vernon R G, Yeaman S J
School of Biochemistry and Genetics, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom.
J Biol Chem. 2000 Feb 18;275(7):5011-5. doi: 10.1074/jbc.275.7.5011.
Adipocyte lipolysis was compared with hormone-sensitive lipase (HSL)/perilipin subcellular distribution and perilipin phosphorylation using Western blot analysis. Under basal conditions, HSL resided predominantly in the cytosol and unphosphorylated perilipin upon the lipid droplet. Upon lipolytic stimulation of adipocytes isolated from young rats with the beta-adrenergic agonist, isoproterenol, HSL translocated from the cytosol to the lipid droplet, but there was no movement of perilipin from the droplet to the cytosol; however, perilipin phosphorylation was observed. By contrast, upon lipolytic stimulation and perilipin phosphorylation in cells from more mature rats, there was no HSL translocation but a significant movement of perilipin away from the lipid droplet. Adipocytes from younger rats had markedly greater rates of lipolysis than those from the older rats. Thus high rates of lipolysis require translocation of HSL to the lipid droplet and translocation of HSL and perilipin can occur independently of each other. A loss of the ability to translocate HSL to the lipid droplet probably contributes to the diminished lipolytic response to catecholamines with age.
使用蛋白质印迹分析比较脂肪细胞脂解与激素敏感性脂肪酶（HSL）/周脂素亚细胞分布及周脂素磷酸化情况。在基础条件下，HSL主要存在于细胞质中，而周脂素在脂滴上未磷酸化。用β-肾上腺素能激动剂异丙肾上腺素刺激从幼鼠分离的脂肪细胞进行脂解时，HSL从细胞质转移至脂滴，但周脂素未从脂滴转移至细胞质；然而，观察到周脂素磷酸化。相比之下，在更成熟大鼠的细胞中进行脂解刺激和周脂素磷酸化时，未观察到HSL转移，但周脂素有明显从脂滴移开的现象。幼鼠的脂肪细胞脂解速率明显高于老年大鼠。因此，高脂解速率需要HSL转移至脂滴，且HSL和周脂素的转移可相互独立发生。HSL转移至脂滴的能力丧失可能导致随年龄增长对儿茶酚胺的脂解反应减弱。
