Figure 5

Itgβ1 blocking antibody inhibits the effects on neurite outgrowth of APPs-α or deletion of APP. (a) E18 primary cortical neurons from wild-type (WT) or APP knock-out (KO) mice were treated with Itgβ1 blocking antibody or control (ctl) antibody. (b) Wild-type E18 neurons were treated with control or APPs-rich CHO CM together with either Itgβ1 blocking or control antibody. The longest βIII-tubulin-positive neurites were quantified. Error bars represent standard error of the mean; ***p < 0.001; ns, not significant. (c, d) CHO cells were transfected with APP-FLAG and Itgβ1 (c) or Itgβ1-FLAG and APP (d). Example of western blot (WB) of co-immunoprecipitates of APP and Itgβ1 after incubation with control (ctl) CM or APPs-α CM (c) or purified His-tagged APPs-α (d) with quantification below; error bars represent standard deviation between duplicate wells. A significant decrease in co-immunoprecipitation between APP and Itgβ1 was observed between multiple experiments; p < 0.05. (e) Model for proposed functional interaction between APP and integrins in regulating neurite elongation.