盘基网柄菌发育期间gp150蛋白与蛋白激酶A相关性的研究

盘基网柄菌进入多细胞发育阶段后，野生型KAx-3细胞的盘基网柄菌蛋白激酶A（DdPKA）活性分别在12，16，20h时显著升高，这一变化趋势与细胞形态学上的分化有关；而突变型AK127细胞（gp150蛋白缺失）的DdPKA活性则一直保持在较高水平，直至22h才缓慢下降。两种细胞类型中24h的DdPKA活性都再一次升高。总体而言，AK127细胞的DdPKA活性要比KAx-3细胞高。这表明AK127细胞可能因缺失了gp150蛋白而导致DdPKA活性调控失去控制。在KAx-3细胞的分化过程中，前柄细胞（prestalk cells，pst）DdPKA的活性在16～18h缓慢上升，但在20h时显著下降；前孢子细胞（prespore cells，psp）中DdPKA的活性在18h时显著下降，但在20h时又迅速恢复，并达到前柄细胞中DdPKA活性的两倍。激光共聚焦结果显示，在KAx-3发育的关键阶段，DdPKA两种亚基的胞内定位并不一致，DdPKA-R亚基在空间位置上更为靠近gp150蛋白，甚至互相重叠。以上结果表明，gp150蛋白可能通过影响DdPKA-R的活性来调控前柄细胞的凋亡和前孢子细胞的分化。

Correlational Study on gp150 and Protein Kinase A During Dictyostelium discoideum Development

When Dictyostelium discoideum entered into post-developmental stage, Dictyostelium discoideum protein kinase A （DdPKA） activity increased significantly at 12 h, 16 h and 20 h time-points in wild-type cells of KAx-3 which was related to cell morphological differentiation. But the DdPKA activity of gp150 knocked out cells （AK127） remained at a relative high level and only decreased apparently at 22 h. However, the DdPKA activity of both stains increased at 24 h. Overall, the DdPKA activity in AK127 was higher than in KAx-3. These showed that the loss of gp150 may lead to the regulation of DdPKA activity get out of control. In addition, DdPKA activity in prestalk cells increased slowly from 16 h to 18 h but decreased rapidly at 20 h, while in prespore cells the activity rose up at 20 h after a decline at 18 h which was almost 2-fold of that in prestalk cells. The colocalization study with laser confocal microscopy showed that the positions of two DdPKA subunits were not together with each other and gp150 was much closer to DdPKA-R, and they even overlapped with each other. The results indicate that the interaction between gp150 and DdPKA-R might influences the apoptosis of prestalk cells and the differentiation of prespore cells.