Movie 4.

Timelapse of β2 integrin activation, quantified by FRET between an integrin headgroup-recognizing antibody labeled with FITC and in the plasma membrane and Octadecyl Rhodamine B in the plasma membrane. The macrophage is undergoing efferocytic synapse formation on a supported lipid bilayer comprised of 20% phosphatidylserine and 80% phosphatidylcholine and opsonized with Gas6 and MFG-E8. Scale bar is 10 μm, 1 frame per minute.