Talin IBS2 Is in Proximity to Integrins in Wing but Not in Muscle
(A–D) FRET analysis to determine the proximity between βPS-GFP and talinIBS2-mCherry (A), vinculin-GFP and talinIBS2-mCherry (B), GFP-talin and vinculin-RFP (C), or GFP-talin and talinIBS2-mCherry (D) at integrin adhesion sites in muscle (left panels) and wing (right panels). Donor GFP (gray in top panels) and GFP lifetime heat maps (lower panels, with scale in ns) are shown. Increasing FRET shortens GFP lifetime; FRET efficiencies are indicated by the standard errors (n > 10) below the panels.
(E) 3D-SIM shows that βPS-GFP (top) and GFP-talin (center) are separated from talinIBS2-mCherry at MASs, in contrast to vinculin-GFP and vinculin-RFP (control for chromatic aberration; bottom).
(F) Diagram of integrin adhesions (orange) between the two epithelial cell layers of the wing. The x-y focal plane of the images is shown with the light blue horizontal plane. Some adhesions are tilted sufficiently to provide a transverse section (dashed black rectangle). Pictures: 3D-SIM x-y sections through wing adhesions show colocalization of βPS-GFP and talinIBS2-mCherry (top), GFP-talin and talinIBS2-mCherry (center), and vinculin-GFP and vinculin-RFP (bottom).