Fig. 5.

PIP2-Moesin-Syk axis is qualitatively similar to but quantitatively less robust than FcR signaling. a Schematic of a series of CD4-EGFP chimeric sequences, with or without a WT or mutated ITAM. b Cos-1, Cos-7, HEK293T, and NIH3T3 cells were transfected with the chimeric molecules by transient overexpression. Empty vector control and FcRIIA for phagocytosis efficiency control were also shown. ***p < 0.001 and ns p > 0.05 by one-way ANOVA with Scheffé post hoc. Phagocytosis efficiency was measured with anti-CD4-coated or IgG-coated 3 µm beads. n = 50, N = 3. c Identical to b except that Moesin KD DC2.4 cells were rescued with the constructs as shown in b. NS was used as a positive control to establish the full capacity of phagocytosis in DC2.4 cells without Moesin knockdown. n = 50, N = 3. ***p < 0.001 and ns p > 0.05 by one-way ANOVA with Scheffé post hoc. d Efficiency of Moesin-dependent (top) and FcR-dependent (bottom) phagocytosis was measured with biotin-BSA-coated beads or IgG-coated beads in shMoesin or shNS treated DC2.4 cells. n = 50, N = 3. *p < 0.5, ****p < 0.0011 and ns p > 0.05 by one-way ANOVA with Scheffé post hoc. e Impact of particle size on the efficiency of Moesin-dependent and FcR-dependent phagocytosis was measured as per phagocytosis assay with 1, 3, or 6 μm biotin-BSA-coated beads (upper) or IgG-coated beads (lower) in RAW264.7 cells. n = 50, N = 4. f To investigate the effects of particle sizes on phagocytosis, phagocytosis assays were performed with 1, 3, 4.5, and 6 μm biotin-BSA-coated (red line) or IgG-coated (black line) polystyrene beads on RAW264.7 cells. The numbers of beads internalized per cell on average were counted for each condition. n = 50, N = 4. *p < 0.05, ****p < 0.0001 and ns p > 0.05 by one-way ANOVA with Scheffé post hoc. g Volume and surface area internalized by RAW264.7 cells in f were calculated from the following formula. Volume = 4/3πr³, and surface area = 4πr². *p < 0.5, ****p < 0.0011, and ns p > 0.05 by one-way ANOVA with Scheffé post hoc