Figure 2.

Activation of αIIbβ3 after talin recruitment to the plasma membrane requires talin binding to the β3 cytoplasmic tail.A, A5 CHO cells were prepared that stably coexpressed C1BN–GFP–CAAX and either CRY2–mCherry–WT talin or one of two CRY2–mCherry–talin constructs (L325R or W359A) known to abrogate talin interaction with the β3 cytoplasmic tail (14). Talin expression was assessed by Western blot using antibodies to talin or to mCherry. β-actin was monitored as a loading control. Note that in the anti-talin antibody blot, the upper region of three immunoreactive bands represents CRY2–mCherry–talin, which was also immunoreactive with the anti-mCherry antibody. B, optogenetic recruitment of integrin β3 tail binding–deficient CRY2–mCherry–talin to the plasma membrane fails to activate αIIbβ3. Data represent the means ± SEM of three experiments (asterisk, p < 0.05). CHO, Chinese hamster ovary; CRY2, Arabidopsis cryptochrome 2; N.S., not statistically significant.