CELL BIOLOGICAL RESEARCH WITH THE MOLECULAR MECHANISMS OF LIPID DROPLETS FORMATION AND LIPID METABOLISM, TRANSFORMATION.

内皮中CAVEOLIN-1的酪氨酸磷酸化1)CAVEOLIN-1的酪氨酸磷酸化发生在有限的位置，包括连续毛细血管和小静脉的内皮。2)在标准培养条件下，培养的内皮细胞不被PY14标记，但当暴露于氧化应激和/或酪氨酸磷酸酶抑制剂时，内皮细胞被标记为阳性。3)用红霉素A或染料木素预处理，可抑制反应。血管活性试剂或物理刺激不会引起磷酸化。4)内陷小泡数量急剧减少，胞质中出现小泡蛋白-1强烈标记的小泡；囊泡的平均直径大于小泡的平均直径。5)实验结果表明，正常大鼠内皮细胞中酪氨酸磷酸化的小泡蛋白-1位点位于酪氨酸-14位点，并可能导致小泡泡形成和/或融合。通过构建针对金鱼黄细胞骨架的单克隆抗体（mAb A2），我们发现一个190 kda的蛋白位于大鼠肺间隔细胞脂滴边缘。2) MAb A2在体内与间隔细胞脂滴边缘结合。在培养的间隔细胞中观察到脂滴周围的环状标记和细胞质中的丝状标记。3)随着培养数天细胞脂滴数量和大小的减少，圆形标记逐渐模糊，丝状标记持续存在。4)在Western blotting中，mAb A2在培养的间隔细胞中识别190-kDa和58-kDa条带，但后者为vimentin。5)用Colcemid处理间隔细胞4小时后，脂滴周围的标记消失，只留下与抗波形蛋白标记模式相匹配的粗束标记。6)给药12小时以上后，脂滴周围又出现圆形标记。紫杉醇或细胞松弛素B处理间隔细胞超过4小时，圆形标记也消失。少

TYROSINE PHSPHORYLATION OF CAVEOLIN-1 IN THE ENDOTHELIUM.1) Tyrosine phosphorylation of caveolin-1 occurred in limited locations, including the endothelium of the continuous capillaries and small venules. 2) Cultured endothelial cells were not labeled by PY14 under a standard culture condition, but became positively labeled when exposed to oxidative stresses and/or tyrosine phosphatase inhibitors. 3) The reaction was prohibited by pretreating with herbimycin A or genistein. Vasoactive reagents or physical stimuli did not cause the phosphorylation. 4) The number of invaginated caveolae decreased drastically, and vesicles labeled intensely for caveolin-1 appeared in the cytoplasm ; the average diameter of the vesicles was larger than that of caveolae. 5) The results implies that tyrosine phosphorylation of caveolin-1 occurred at tyrosine-14 in the normal rat endothelium in vivo and may induce caveolar vesiculation and/or fusion.VIMEMTIN-RELATED ANTIGEN AROUND LIPID DROPLETE1) By using a … More monoclonal antibody (mAb A2) raised against the cytoskeleton of goldfish xanthophores, we found that a 190-kDa protein is localized along the rim of lipid droplets in rat pulmonary septal cells. 2) MAb A2 bound to the rim of lipid droplets in the septal cell in vivo. The circular labeling around lipid droplets as well as filamentous labeling in the cytoplasm was observed in cultured septal cells. 3) As the number and size of lipid droplets decreased in cells cultured for several days, the circular labeling became indistinct, whereas the filamentous labeling persisted. 4) In Western blotting, mAb A2 recognized 190-kDa and 58-kDa bands in the cultured septal cell, but the latter turned out to be vimentin. 5) Treatment of septal cells for 4 hr with Colcemid extinguished the labeling around the lipid droplets, and only labeling in a coarse bundle pattern that matched the anti-vimentin labeling pattern remained. 6) After more than 12 hr of Colcemid treatment, the circular labeling reappeared around the lipid droplets. The disappearance of the circular labeling also occurred when septal cells were treated with Taxol or cytochalasin B for more than 4 hr. Less