Fig. 4

PI(3,4,5)P₃ and actin display coordinated but diffuse distributions around FcγR-IgG clusters. BtkPH (green, a) and actin (cyan, b) were distributed along the leading edge of the advancing pseudopod, near or behind clustered FcγR-IgG (magenta). FcγR-IgG clusters departed from the leading edge have both BtkPH and actin near, but not coincident with them; scale bar 10 μm. c FcγR-IgG microclusters were tracked, and color-coded, green – outward, red – inward; the tracking was done on one cell with a total number of 172 tracks; scale bar 10 μm. d Analysis of single IgG clusters showed diffuse recruitment of BtkPH consistent with PI(3,4,5)P₃‘s ability to diffuse in the membrane and with actin polymerization in areas rich in PI(3,4,5)P₃; the width of the montage panel 2 μm. e-f Intensity traces from the track in (d) indicated that while the IgG signal remained constant in the cluster (e), the associated BtkPH (f) and actin (g) signals underwent coincident transients that were correlated to the motion of the FcγR-IgG clusters; color coding is the same as in (c). The black line indicates the local background signal