Movie 1.

Timelapse of β2 integrin activation on macrophages interacting with apoptotic cell mimics opsonized with the MERTK opsonin Gas6. Top-left shows a DIC image, yellow is the donor fluorophore attached to β2 integrin, magenta is the acceptor Octadecyl Rhodamine B. Heatmap shows the inverted FRET signal quantifying β2 integrin activation. Scale bar is 10 μm, 1 frame per minute.