Axelrod J D
Department of Pathology, Stanford University School of Medicine, Stanford, California 94305-5324, USA.
Genes Dev. 2001 May 15;15(10):1182-7. doi: 10.1101/gad.890501.
Drosophila epithelia acquire a planar cell polarity (PCP) orthogonal to their apical-basal axes. Frizzled (Fz) is the receptor for the PCP signal, and Dishevelled (Dsh) transduces the signal. Here, I demonstrate that unipolar relocalization of Dsh to the membrane is required to mediate PCP, but not Wingless (Wg) signaling. Dsh membrane localization reflects the activation of Fz/PCP signaling, revealing that the initially symmetric signal evolves to one that displays unipolar asymmetry, specifying the cells' ultimate polarity. This transition from symmetric to asymmetric Dsh localization requires Dsh function, and reflects an amplification process that generates a steep intracellular activity gradient necessary to determine PCP.
果蝇上皮细胞获得了与其顶-基轴正交的平面细胞极性(PCP)。卷曲蛋白(Fz)是PCP信号的受体,而散乱蛋白(Dsh)则传导该信号。在此,我证明Dsh单极重新定位到膜上是介导PCP所必需的,但不是无翅(Wg)信号传导所必需的。Dsh膜定位反映了Fz/PCP信号传导的激活,揭示了最初对称的信号演变为显示单极不对称性的信号,从而确定细胞的最终极性。Dsh定位从对称到不对称的这种转变需要Dsh发挥功能,并反映了一个放大过程,该过程产生了确定PCP所需的陡峭的细胞内活性梯度。