Fig. 3.
The α-integrin CT MD region is required for talin- and kindlin-induced integrin activation. (A–C) Complete deletion of the α-integrin CT MD region abolished talin-1-head-induced activation of (A) αIIbβ3, (B) αVβ3, and (C) αLβ2 integrins. Ligand binding was measured by flow cytometry with 293FT cells co-transfected with the indicated integrin constructs (also shown schematically above the bars) and EGFP or EGFP–TH. The EGFP and integrin double-positive cells were analyzed. (D–F) The α-integrin CT MD region is required for kindlin-induced activation of (D) αIIbβ3, (E) αVβ3, and (F) αLβ2 integrins. Ligand binding was measured by flow cytometry with 293FT cells co-transfected with the indicated integrin constructs and EGFP–TH plus mCherry (mC), mC-tagged kindlin-2 (mC–K2), or mC-tagged kindlin-3 (mC–K3). The integrin, EGFP, and mCherry triple-positive cells were analyzed. Data are presented as the MFI of the ligand normalized to integrin expression. Data are presented as mean±s.e.m. (n≥3). *P<0.05; **P<0.01; ns, not significant (unpaired two-tailed Student's t-tests).