Roth D, Burgoyne R D
Physiological Laboratory, University of Liverpool, UK.
FEBS Lett. 1995 Oct 23;374(1):77-81. doi: 10.1016/0014-5793(95)01080-x.
Catecholamine release from digitonin-permeabilized adrenal chromaffin cells is increased by exogenous 14-3-3 proteins. In order to determine how 14-3-3 proteins stimulate exocytosis their effect on the cortical actin network was examined. Increased amounts of beta and gamma isoforms of 14-3-3 proteins were associated with the Triton-insoluble cytoskeleton of chromaffin cells following incubation with exogenous 14-3-3 proteins. The stimulation of catecholamine release by 14-3-3 proteins was abolished by prior incubation with the actin filament stabilising drug phalloidin. Rhodamine phalloidin staining showed that the cortical actin network was disassembled and actin reorganised into intracellular foci following treatment with 14-3-3 proteins. These data suggest that 14-3-3 proteins enhance catecholamine release in permeabilized chromaffin cells by reorganisation of the cortical actin barrier to allow increased availability of secretory vesicles for exocytosis.
外源性14-3-3蛋白可增加洋地黄皂苷通透处理的肾上腺嗜铬细胞中儿茶酚胺的释放。为了确定14-3-3蛋白如何刺激胞吐作用，研究了其对皮质肌动蛋白网络的影响。与外源性14-3-3蛋白孵育后，嗜铬细胞的Triton不溶性细胞骨架中14-3-3蛋白的β和γ亚型含量增加。预先用肌动蛋白丝稳定药物鬼笔环肽孵育可消除14-3-3蛋白对儿茶酚胺释放的刺激作用。罗丹明鬼笔环肽染色显示，用14-3-3蛋白处理后，皮质肌动蛋白网络被分解，肌动蛋白重新组织成细胞内焦点。这些数据表明，14-3-3蛋白通过重组皮质肌动蛋白屏障来增强通透化嗜铬细胞中儿茶酚胺的释放，从而使分泌囊泡有更多机会用于胞吐作用。
