Fig. 3: Gβ4 deficiency alters cell migration and crosstalk between phagocytosis and motility.
A, Schematic of the micropipette-based chemotaxis assay. B-F, ΔGβ4 and WT HL-60 neutrophils were seeded onto fibronectin coated slides and exposed to 200 nM fMLF delivered through a micropipette over the course of an hour. Alternatively, ΔGβ4 and WT cells that had consumed 1 MP (WT + 1MP and ΔGβ4 + 1MP) were sorted, seeded at a 1:1 ratio on fibronectin coated glass, and exposed to 200 nM fMLF through a micropipette for one hour. B, Mean velocity of ΔGβ4 and WT HL-60 neutrophils during the first 15 minutes of the time course. C, Mean velocities of WT, WT + 1MP, ΔGβ4, and ΔGβ4 + 1MP cells were calculated from 3 separate 1 hour videos. D, Time-lapse montages of representative cells in each experimental group, with the red arrow indicating the direction of the fMLF gradient. Yellow asterisks denote a transient loss of migratory cell polarity in a WT + 1MP cell. White arrows indicate cell body regression in a ΔGβ4 cell with an extended uropod. Scale bars = 20 μm. E, Total distance travelled by WT + 1MP and ΔGβ4 + 1MP cells after 1 hour of exposure to 200 nM fMLF. F, Representative migration tracks for WT + 1MP and ΔGβ4 + 1MP over the course of 1 hour exposure to 200 nM fMLF. Violins in B, C and E encompass the entire distribution, with solid horizontal lines indicating the median and dotted lines indicating the upper and lower quartiles. *** p< 0.001 and **** p< 0.0001, calculated by unpaired t-test (E) or two-way ANOVA (C). n ≥ 174 for each sample, pooled from 3 biological replicates.