Figure 9

Localization of probes in cells expressing both mRFP-FLN and GFP-αA. In order to directly verify that these actin binding proteins localize to different parts of the actin cytoskeleton, a new cell line was made that expressed both a red fluorescent filamin (FLN-mRFP) and GFP-αA. The cells were imaged during polarized chemotaxis to cAMP. A sequence of confocal images acquired in both channels and then merged is shown. The cell was moving upward and has paused in panel A. It then initiates pseudopod protrusion to the right (arrow in panels B-D) and then moves in that direction (panels E-H). Both probes localize to the new protrusion, but as the cell begins to move, the filamin probe is lost from the protrusion and is found only in the rear portion of the cell (arrowhead in panel G) while the a-actinin probe is in the front (arrow in panel G). (See also the movie in Additional File 5)