Ueda M, Gräf R, MacWilliams H K, Schliwa M, Euteneuer U
Adolf Butenandt Institute, Cell Biology, University of Munich, Munich, Germany.
Proc Natl Acad Sci U S A. 1997 Sep 2;94(18):9674-8. doi: 10.1073/pnas.94.18.9674.
In several cell types, an intriguing correlation exists between the position of the centrosome and the direction of cell movement: the centrosome is located behind the leading edge, suggesting that it serves as a steering device for directional movement. A logical extension of this suggestion is that a change in the direction of cell movement is preceded by a reorientation, or shift, of the centrosome in the intended direction of movement. We have used a fusion protein of green fluorescent protein (GFP) and gamma-tubulin to label the centrosome in migrating amoebae of Dictyostelium discoideum, allowing us to determine the relationship of centrosome positioning and the direction of cell movement with high spatial and temporal resolution in living cells. We find that the extension of a new pseudopod in a migrating cell precedes centrosome repositioning. An average of 12 sec elapses between the initiation of pseudopod extension and reorientation of the centrosome. If no reorientation occurs within approximately 30 sec, the pseudopod is retracted. Thus the centrosome does not direct a cell's migration. However, its repositioning stabilizes a chosen direction of movement, most probably by means of the microtubule system.
在几种细胞类型中，中心体的位置与细胞运动方向之间存在一种有趣的相关性：中心体位于前缘之后，这表明它充当了定向运动的导向装置。该观点的一个合理延伸是，细胞运动方向的改变之前，中心体在预期运动方向上会重新定向或移位。我们利用绿色荧光蛋白（GFP）与γ-微管蛋白的融合蛋白，标记盘基网柄菌迁移变形虫中的中心体，从而使我们能够在活细胞中以高时空分辨率确定中心体定位与细胞运动方向之间的关系。我们发现，迁移细胞中新伪足的伸出先于中心体重新定位。从伪足伸出开始到中心体重新定向，平均经过12秒。如果在大约30秒内没有发生重新定向，伪足就会缩回。因此，中心体并不指导细胞的迁移。然而，它的重新定位稳定了所选择的运动方向，很可能是通过微管系统实现的。
