Fig. 1. PH domain and PI3K localization. The upper panel illustrates the temporal localization of the PH-domain-containing protein PhdA to the plasma membrane in response to a directional signal. In the first panel (left), the micropipette (asterisk) is in the upper right-hand corner and there is a localization of the protein in the part of the cell closest to the micropipette. In the second panel, the micropipette has moved, leading to a delocalization of PhdA from the original site and localization to the new position of the micropipette (panel 3). The fourth panel (right) indicates that when the micropipette is moved again, there is once again a delocalization of PhdA from the old site and a relocalization to the new site of the micropipette. The lower panels illustrate a similar dynamic localization of PI3K to the position on the plasma membrane closest to the chemoattractant source. The first panel shows the localization on the right side of the cell. When the micropipette is moved, there is a loss of this localization and a relocalization to the new position on the membrane. This localization is not sensitive to latrunculin A (data not shown), indicating that it is not dependent on the actin cytoskeleton.