Wang S M, Fong T H
Department of Anatomy, College of Medicine, National Taiwan University, Taipei, Republic of China.
Biochem Biophys Res Commun. 1995 Dec 5;217(1):81-8. doi: 10.1006/bbrc.1995.2748.
We have used a monoclonal antibody, A2, to study the structure and function on the lipid droplet capsule in steroidogenic adrenal cells. This antibody reacts with a 160-kD protein found in the rat adrenal cortex. Immunofluorescence microscopy shows a dominant rim pattern, which surrounds individual lipid droplets and is distinct from the filamentous vimentin staining. The boundary of lipid droplets in steroidgenic Leydig cells and 3T3 adipocytes is also immunostained by this antibody. The strong association of the 160-kD protein with the lipid droplet is demonstrated by its resistance to Triton X-100 extraction. Stimulation of steroid secretion by adrenocorticotropin results in the detachment of this protein from the lipid droplet and its movement to the cytosol. These findings suggest that the translocation of this 160-kD protein from lipid droplet surface to cytosol on stimulation might be important in facilitating the binding of cholesterol ester hydrolase to the surface of lipid droplets, as proposed for adipocytes, during lipolytic stimulation.
我们使用了一种单克隆抗体A2来研究类固醇生成性肾上腺细胞中脂滴包膜的结构和功能。这种抗体与在大鼠肾上腺皮质中发现的一种160-kD蛋白发生反应。免疫荧光显微镜显示出一种主要的边缘模式，它围绕着单个脂滴，并且与丝状波形蛋白染色不同。该抗体也对类固醇生成性睾丸间质细胞和3T3脂肪细胞中的脂滴边界进行免疫染色。160-kD蛋白与脂滴的强关联通过其对Triton X-100提取的抗性得以证明。促肾上腺皮质激素刺激类固醇分泌会导致该蛋白从脂滴上脱离并移动到细胞质中。这些发现表明，如在脂肪细胞脂解刺激过程中所提出的那样，刺激时这种160-kD蛋白从脂滴表面向细胞质的易位可能在促进胆固醇酯水解酶与脂滴表面的结合中起重要作用。
