Fig. 5.

Toll-GFP exhibits limited diffusion within the plasma membrane and is compartmentalized within the endocytic pathway. (A) Photoactivation of Toll-paGFP on the plasma membrane surface. Toll within the plasma membrane at nuclear cycle 14 diffuses one to two cell diameters within 20 min at 22 °C. PRE, preinjection; POST, postinjection. (B) FRAP of both the membrane and particulate fractions of Toll (bleach box in red). (C) Fluorescence recovery curves for the plasma membrane fraction (blue) and the particulate fraction (red) illustrate slow recovery for membrane-localized Toll over a distance of one future blastoderm cell. The recovery rate for particulate Toll (red) is 20% of the recovery rate for the plasma membrane fraction.