Figure 7.

WIPa is necessary for prompt response to a changing chemoattractant gradient. (A) Pulsed cells were allowed to chemotax toward a cAMP-releasing micropipette (*) for ∼5 min. Time 0 indicates the first frame after which the micropipette was moved to its new position. Time-lapsed images were taken at 5 s intervals for a total of ∼90 frames. Chemotactic parameters of each cell type were averaged from three independent experiments (AX3 = 35 cells total; hp WIPa = 38 cells total). (B) Instantaneous velocity of each cell type after micropipette shift as tracked by Metamorph. Averages of 10 cells of each type from three independent experiments are shown. (C) hp WIPa cells require more time to initiate membrane protrusion and subsequently pseudopodia formation, toward the direction of the new gradient. (D) The average time required for forming new pseudopodia toward the new cAMP source.